[US Patent & Trademark Office, Patent Full Text and Image Database]
[Home] [Boolean Search] [Manual Search] [Number Search] [Help]
[HIT_LIST] [NEXT_LIST] [PREV_DOC] [NEXT_DOC] [Bottom]
[View Shopp ing Cart] [Add to Shopping Cart]
[Image]
  ( 29 of 186 )
United States Patent 10,823,052
Schwarz November 3, 2020
Geared turbofan engine with targeted modular efficiency

Abstract

A turbofan engine includes a fan section including a fan blade having a leading edge and hub to tip ratio of less than about 0.34 and greater than about 0.020 measured at the leading edge and a speed change mechanism with gear ratio greater than about 2.6 to 1. A first compression section includes a last blade trailing edge radial tip length that is greater than about 67% of the radial tip length of a leading edge of a first stage of the first compression section. A second compression section includes a last blade trailing edge radial tip length that is greater than about 57% of a radial tip length of a leading edge of a first stage of the first compression section.

Inventors: Schwarz; Frederick M. (Glastonbury, CT)
Applicant:
Name City State Country Type

Raytheon Technologies Corporation
Farmington
CT
US
Assignee: Raytheon Technologies Corporation (Farmington, CT)
Family ID: 53371941
Appl. No.: 16/531,704
Filed: August 5, 2019
Prior Publication Data
Document IdentifierPublication Date
US 20190353098 A1Nov 21, 2019
Related U.S. Patent Documents
Application NumberFiling DatePatent NumberIssue Date
1465192310371047
PCT/US2014/057127Sep 24, 2014
61891475Oct 16, 2013

Current U.S. Class: 1/1
Current CPC Class: F02K 3/06 (20130101); F02C 3/107 (20130101); F01D 5/142 (20130101); F05D 2260/40311 (20130101); F05D 2220/327 (20130101); Y02T 50/60 (20130101); F05D 2220/36 (20130101)
Current International Class: F02C 3/107 (20060101); F02K 3/06 (20060101); F01D 5/14 (20060101)

References Cited [Referenced By]
U.S. Patent Documents
2258792 April 1941 New
2936655 May 1960 Peterson et al.
3021731 February 1962 Stoeckicht
3194487 July 1965 Tyler et al.
3287906 November 1966 McCormick
3352178 November 1967 Lindgren et al.
3363419 January 1968 Wilde
3412560 November 1968 Gaubatz
3664612 May 1972 Skidmore et al.
3747343 July 1973 Rosen
3754484 August 1973 Roberts
3765623 October 1973 Donelson et al.
3820719 June 1974 Clark
3843277 October 1974 Ehrich
3892358 July 1975 Gisslen
3932058 January 1976 Harner et al.
3935558 January 1976 Miller et al.
3988889 November 1976 Chamay et al.
4118927 October 1978 Kronogard
4130872 December 1978 Harloff
4220171 September 1980 Ruehr
4240250 December 1980 Harris
4284174 August 1981 Salvana et al.
4289360 September 1981 Zirin
4478551 October 1984 Honeycutt, Jr. et al.
4649114 March 1987 Miltenburger et al.
4696156 September 1987 Burr et al.
4722357 February 1988 Wynosky
4860537 August 1989 Taylor
4966338 October 1990 Gordon
4979362 December 1990 Vershure, Jr.
5058617 October 1991 Stockman et al.
5102379 April 1992 Pagluica et al.
5136839 August 1992 Armstrong
5141400 August 1992 Murphy et al.
5174525 December 1992 Schilling
5273393 December 1993 Jones et al.
5275357 January 1994 Seelan et al.
5277382 January 1994 Seelan et al.
5317877 June 1994 Stuart
5320307 June 1994 Spofford et al.
5361580 November 1994 Ciokajlo et al.
5372338 December 1994 Carlin
5409184 April 1995 Udall et al.
5433674 July 1995 Sheridan et al.
5443229 August 1995 O'Brien et al.
5447411 September 1995 Curley et al.
5452575 September 1995 Freid
5466198 November 1995 McKibbin et al.
5474258 December 1995 Taylor et al.
5497961 March 1996 Newton
5524847 June 1996 Brodell et al.
5634767 June 1997 Dawson
5677060 October 1997 Terentieva et al.
5694765 December 1997 Hield et al.
5746391 May 1998 Rodgers et al.
5778659 July 1998 Duesler et al.
5810287 September 1998 O'Boyle et al.
5857836 January 1999 Stickler et al.
5860276 January 1999 Newton
5871175 February 1999 Demouzon et al.
5871176 February 1999 Demouzon et al.
5871177 February 1999 Demouzon et al.
5915917 June 1999 Eveker et al.
5921500 July 1999 Ellis et al.
5927644 July 1999 Ellis et al.
5975841 November 1999 Lindemuth et al.
5985470 November 1999 Spitsberg et al.
6126110 October 2000 Seaquist et al.
6138949 October 2000 Manende et al.
6189830 February 2001 Schnelz et al.
6223616 May 2001 Sheridan
6315815 November 2001 Spadaccini et al.
6318070 November 2001 Rey et al.
6387456 May 2002 Eaton, Jr. et al.
6474597 November 2002 Cazanave
6517027 February 2003 Abruzzese
6517341 February 2003 Brun et al.
6607165 August 2003 Manteiga et al.
6652222 November 2003 Wojtyczka et al.
6708925 March 2004 Udall
6709492 March 2004 Spadaccini et al.
6814541 November 2004 Evans et al.
6843449 January 2005 Manteiga et al.
6883303 April 2005 Seda
6899518 May 2005 Lucas et al.
6935591 August 2005 Udall
6976655 December 2005 Thompson
7021042 April 2006 Law
7021585 April 2006 Loewenstein et al.
7055330 June 2006 Miller
7134286 November 2006 Markarian et al.
7219490 January 2007 Dev
7328580 February 2008 Lee et al.
7374403 May 2008 Decker et al.
7500365 March 2009 Suciu et al.
7527220 May 2009 Dron
7591754 September 2009 Duong et al.
7632064 December 2009 Somanath
7662059 February 2010 McCune
7806651 October 2010 Kennepohl et al.
7824305 November 2010 Duong et al.
7828682 November 2010 Smook
7882691 February 2011 Lemmers et al.
7926260 April 2011 Sheridan et al.
7942079 May 2011 Russ
7942580 May 2011 Audart-Noel et al.
7997868 August 2011 Liang et al.
8205432 June 2012 Sheridan
8220245 July 2012 Papandreas
10371047 August 2019 Schwarz
2003/0163983 September 2003 Seda et al.
2006/0090448 May 2006 Henry
2006/0228206 October 2006 Decker et al.
2006/0248900 November 2006 Suciu et al.
2008/0003096 January 2008 Kohli et al.
2008/0116009 May 2008 Sheridan et al.
2008/0317588 December 2008 Grabowski et al.
2009/0007569 January 2009 Lemmers et al.
2009/0053058 February 2009 Kohlenberg et al.
2009/0056343 March 2009 Suciu et al.
2009/0245997 October 2009 Hurwitz et al.
2009/0304518 December 2009 Kodama et al.
2009/0314881 December 2009 Suciu et al.
2010/0003121 January 2010 Berryann et al.
2010/0105516 April 2010 Sheridan et al.
2010/0147997 June 2010 Martinou et al.
2010/0148396 June 2010 Xie et al.
2010/0170980 July 2010 Haramburu et al.
2010/0181419 July 2010 Haramburu et al.
2010/0212281 August 2010 Sheridan
2010/0218483 September 2010 Smith
2010/0331139 December 2010 McCune
2011/0114786 May 2011 Guillet et al.
2011/0159797 June 2011 Beltman et al.
2011/0293423 December 2011 Bunker et al.
2012/0124964 May 2012 Hasel et al.
2012/0291449 November 2012 Adams et al.
2013/0192198 August 2013 Brilliant et al.
2013/0192258 August 2013 Kupratis et al.
Foreign Patent Documents
0791383 Aug 1997 EP
1142850 Oct 2001 EP
1516041 Jun 1978 GB
2041090 Sep 1980 GB
2426792 Dec 2006 GB
2007038674 Apr 2007 WO

Other References

Honeywell LF507. Jane's Aero-engines, Aero-engines--Turbofan. Feb. 9, 2012. cited by applicant .
Honeywell TFE731. Jane's Aero-engines, Aero-engines--Turbofan. Jul. 18, 2012. cited by applicant .
NASA Conference Publication. Quiet, powered-lift propulsion. Cleveland, Ohio. Nov. 14-15, 1978. pp. 1-420. cited by applicant .
"Civil Turbojet/Turbofan Specifications", Jet Engine Specification Database (Apr. 3, 2005). cited by applicant .
Kandebo, S.M. (1993). Geared-turbofan engine design targets cost, complexity. Aviation Week & Space Technology, 148(8). Start p. 32. cited by applicant .
Hendricks, E.S. and Tong, M.T. (2012). Performance and weight estimates for an advanced open rotor engine. NASA/TM-2012-217710. pp. 1-13. cited by applicant .
Guynn, M. D., Berton, J.J., Fisher, K. L, Haller, W.J., Tong, M. T., and Thurman, Dr. (2011). Refined exploration of turbofan design options for an advanced single-aisle transport. NASA/TM-2011-216883. pp. 1-27. cited by applicant .
Zalud, T. (1998). Gears put a new spin on turbofan performance. Machine Design, 70(20), p. 104. cited by applicant .
Kurzke, J. (2008). Preliminary Design, Aero-engine design: From state of the art turbofans towards innovative architectures. pp. 1-72. cited by applicant .
Zamboni, G. and Xu, L. (2009). Fan root aerodynamics for large bypass gas turbine engines: Influence on the engine performance and 3D design. Proceedings of ASME Turbo Expo 2009: Power for Land, Sea and Air. Jun. 8-12, 2009, Orlando, Florida, USA. pp. 1-12. cited by applicant .
Han, J., Dutta, S., and Ekkad, S.V. (2000). Gas turbine heat transfer and cooling technology. New York, NY: Taylor & Francis. pp. 1-25, 129-157, and 160-249. cited by applicant .
Mattingly, J.D. (1996). Elements of gas turbine propulsion. New York, New York: McGraw-Hill, Inc. pp. 1-18, 60-62, 85-87, 95-104, 121-123, 223-234, 242-245, 278-280, 303-309, 323-326, 462-479, 517-520, 563-565, 673-675, 682-685, 697-699, 703-705, 802-805, 862-864, and 923-925. cited by applicant .
Declaration of Reza Abhari, Ph.D. In re U.S. Pat. No. 8,844,265. Executed Jun. 28, 2016. pp. 1-91. cited by applicant .
Declaration of John Eaton, Ph.D. In re U.S. Pat. No. 8,869,568. Executed Mar. 28, 2016. pp. 1-87. cited by applicant .
Declaration of Reza Abhari. In re U.S. Pat. No. 8,695,920. Executed Nov. 30. pp. 1-67. cited by applicant .
Declaration of Reza Abhari. In re U.S. Pat. No. 8,448,895. Executed Nov. 28. pp. 1-81. cited by applicant .
Declaration of Reza Abhari. In re U.S. Pat. No. 8,695,920, claims 1-4, 7-14, 17 and 19. Executed Nov. 29. pp. 1-102. cited by applicant .
Declaration of Dr. Magdy Attia. In re U.S. Pat. No. 8,313,280. Executed Oct. 21, 2016. pp. 1-88. cited by applicant .
Lord, W.K., Macmartin, D.G., and Tillman, T.G. (2000). Flow control opportunities in gas turbine engines. American Institute of Aeronautics and Astronautics. pp. 1-15. cited by applicant .
Daly, M. Ed. (2010). Jane's Aero-Engine. Issue Twenty-seven. Mar. 2010. p. 633-636. cited by applicant .
Roux, E. (2007). Turbofan and turbojet engines database handbook. Editions Elodie Roux. Blagnac: France. pp. 1-595. cited by applicant .
Wilfert, G. (2008). Geared fan. Aero-Engine Design: From State of the Art Turbofans Towards Innovative Architectures, von Karman Institute for Fluid Dynamics, Belgium, Mar. 3-7, 2008. pp. 1-26. cited by applicant .
Declaration of Dr. Magdy Attia. In re U.S. Pat. No. 8,517,668. Executed Dec. 8, 2016. pp. 1-81. cited by applicant .
Cramoisi, G. Ed. (2012). Death in the Potomac: The crash of Air Florida Flight 90. Air Crash Investigations. Accident Report NTSB/AAR-82-8. p. 45-47. cited by applicant .
Norton, M. and Karczub, D. (2003). Fundamentals of noise and vibration analysis for engineers. Press Syndicate of the University of Cambridge. New York: New York. p. 524. cited by applicant .
U.S. Department of Transportation: Federal Aviation Administration Advisory Circular. Runway overrun prevention. Dated: Nov. 6, 2007. p. 1-8 and Appendix 1 p. 1-15, Appendix 2 p. 1-6, Appendix 3 p. 1-3, and Appendix 4 p. 1-5. cited by applicant .
U.S. Department of Transportation: Federal Aviation Administration Advisory Circular. Standard operating procedures for flight deck crewmembers. Dated: Feb. 27, 2003.. p. 1-6 and Appendices. cited by applicant .
Vasudevan, A.K. and Petrovic, J.J. (1992). A comparative overview of molybedenum disilicide composites. Materials Science and Engineering, A155, 1992. pp. 1-17. cited by applicant .
Clarke, D.R. and Levi, C.G. (2003). Materials design for the next generation thermal barrier coatings. Annual. Rev. Mater. Res. vol. 33. 2003. pp. 383-417. cited by applicant .
Lee, K.N. (2000). Current status of environmental barrier coatings for Si-Based ceramics. Surface and Coatings Technology 133-134, 2000. pp. 1-7. cited by applicant .
Bornstein, N. (1993). Oxidation of advanced intermetallic compounds. Journal de Physique IV, 1993, 03 (C9), pp. C9-367-C9-373. cited by applicant .
Krenkel, W., Naslain, R., and Schneider, H. Eds. (2001). High temperature ceramic matrix composites pp. 224-229. Weinheim, DE: Wiley-VCH Verlag GmbH. cited by applicant .
Gibala, R., Ghosh, A.K., Van Aken, D.C., Srolovitz, D.J., Basu, A., Chang, H., . . . Yang, W. (1992). Mechanical behavior and interface design of MoSi2-based alloys and composites. Materials Science and Engineering, A155, 1992. pp. 147-158. cited by applicant .
Shah, D.M. (1992). MoSi2 and other silicides as high temperature structural materials. Superalloys 1992. The Minerals, Metals, & Materials Society. pp. 409-422. cited by applicant .
Zhao, J.C. and Westbrook, J.H. (2003). Ultrahigh-temperature materials for jet engines. MRS Bulletin. vol. 28(9). Sep. 2003. pp. 622-630. cited by applicant .
Tsirlin, M., Pronin, Y.E., Florina, E.K., Mukhametov, S. Kh., Khatsernov, M.A., Yun, H.M., . . . Kroke, E. (2001). Experimental investigation of multifunctional interphase coatings on SiC fibers for non-oxide high temperature resistant CMCs. High Temperature Ceramic Matrix Composites. 4th Int'l Conf. on High Temp. Ceramic Matrix Composites. Oct. 1-3, 2001. pp. 149-156. cited by applicant .
Jacobson, N.S. (1993). Corrosion of silicon-based ceramics in combustion environments. J. Am. Ceram. Soc. 76(1). pp. 3-28. cited by applicant .
Jorgensen, P.J., Wadsworth, M.E., and Cutler, I.B. (1961). Effects of water vapor on oxidation of silicon carbide. J. Am. Ceram. Soc. 44(6). pp. 248-261. cited by applicant .
Xu, Y., Cheng, L., Zhang, L., Ying, H., and Zhou, W. (1999). Oxidation behavior and mechanical properties of C/SiC composites with Si--MoSi2 oxidation protection coating. J. of Mat. Sci. vol. 34. 1999. pp. 6009-6014. cited by applicant .
Sundaram, S.K., Hsu, J-Y., Speyer, R.F. (1995). Molten glass corrosion resistance of immersed combustion-heating tube materials in e-glass. J. Am. Ceram. Soc. 78(7). pp. 1940-1946. cited by applicant .
Jeng, Y.-L., Lavernia, E.J. (1994). Processing of molybdenum disilicide. J. of Mat. Sci. vol. 29. 1994. pp. 2557-2571. cited by applicant .
Suzuki, Y., Morgan, P.E.D., and Niihara, K. (1998). Improvement in mechanical properties of powder-processed MoSi2 by the addition of Sc2O3 and Y2O3. J. Am. Ceram. Soci. 81(12). pp. 3141-3149. cited by applicant .
Webster, J.D., Westwood, M.E., Hayes, F.H., Day, R.J., Taylor, R., Duran, A., . . . Vogel, W.D. (1998). Oxidation protection coatings for C/SiC based on yttrium silicate. Journal of European Ceramic Society vol. 18. 1998. pp. 2345-2350. cited by applicant .
Petrovic, J.J., Castro, R.G., Vaidya, R.U., Peters, M.I., Mendoza, D., Hoover, R.C., and Gallegos, D.E. (2001). Molybdenum disilicide materials for glass melting sensor sheaths. Ceramic Engineering and Science Proceedings. vol. 22(3). 2001. pp. 59-64. cited by applicant .
Kahn, H., Tayebi, N., Ballarini, R., Mullen, R.L., Heuer, A.H. (2000). Fracture toughness of polysilicon MEMS devices. Sensors and Actuators vol. 82. 2000. pp. 274-280. cited by applicant .
Muhlstein, C.L., Stach, E.A., and Ritchie, R.O. (2002). A reaction-layer mechanism for the delayed failure of micron-scale polycrystalline silicon structural films subjected to high-cycle fatigue loading. Acta Materialia vol. 50. 2002. pp. 3579-3595. cited by applicant .
Sundaram, S.K., Hsu, J-Y., Speyer, R.F. (1994). Molten glass corrosion resistance of immersed combustion-heating tube materials in soda-lime-silicate glass. J. Am. Ceram. Soc. 77(6). pp. 1613-1623. cited by applicant .
Leckie, F.A. and Dal Bello, D.J. (2009). Strength and stiffness of engineering systems. Mechanical Engineering Series. Springer. pp. 1-3. cited by applicant .
El-Sayad, A.F. (2008). Aircraft propulsion and gas turbine engines. Boca Raton, FL: CRC Press. pp. 215-219 and 855-860. cited by applicant .
Bunker, R.S. (2005). A review of shaped hole turbine film-cooling technology. Journal of Heat Transfer vol. 127. Apr. 2005. pp. 441-453. cited by applicant .
Winn, A. (Ed). (1990). Wide Chord Fan Club. Flight International, 4217(137). May 23-29, 1990. pp. 34-38. cited by applicant .
Parker, R.G. and Lin, J. (2001). Modeling, modal properties, and mesh stiffness variation instabilities of planetary gears. Prepared for NASA. NASA/CR-2001-210939. May 2001. pp. 1-111. cited by applicant .
Mancuso, J.R. and Corcoran, J.P. (2003). What are the differences in high performance flexible couplings for turbomachinery? Proceedings of the Thirty-Second Turbomachinery Symposium. 2003. pp. 189-207. cited by applicant .
Dudley, D.W., Ed. (1954). Handbook of practical gear design. Lancaster, PA: Technomic Publishing Company, Inc. pp. 3.96-102 and 8.12-18. cited by applicant .
Dudley, D.W., Ed. (1962). Gear handbook. New York, NY: McGraw-Hill. pp. 3.14-18 and 12.7-12.21. cited by applicant .
Dudley, D.W., Ed. (1994). Practical gear design. New York, NY: McGraw-Hill. pp. 119-124. cited by applicant .
Product Brochure. Garrett TFE731. Allied Signal. Copyright 1987. pp. 1-24. cited by applicant .
Honeywell Learjet 31 and 35/36 TFE731-2 to 2C Engine Upgrade Program. Sep. 2005. pp. 1-4. cited by applicant .
Honeywell Sabreliner 65 TFE731-3 to -3D Engine Upgrade Program. Oct. 2005. pp. 1-4. cited by applicant .
U.S. Department of Transportation: Federal Aviation Administration Type Certificate Data Sheet No. E6WE. Dated: May 9, 2000. p. 1-9. cited by applicant .
Kurzke, J. (2012). GasTurb 12: Design and off-design performance of gas turbines. Retrieved from: https://www.scribd.com/document/153900429/GasTurb-12. cited by applicant .
Ahmad, F. and Mizramoghadam, A.V. (1999). Single v. two stage high pressure turbine design of modern aero angines. ASME. Presented at the International Gas Turbine & Aeroengine Congress & Exhibition. Indianapolis, Indiana. Jun. 7-10, 1999. pp. 1-9. cited by applicant .
Riegler, C., and Bichlmaier, C. (2007). The geared turbofan technology--Opportunities, challenges and readiness status. Porceedings CEAS. Sep. 10-13, 2007. Berlin, Germany. pp. 1-12. cited by applicant .
About GasTurb. Retrieved Jun. 26, 2018 from: http://gasturb.de/about-gasturb.html. cited by applicant .
Kurzke, J. (2001). GasTurb 9: A program to calculate design and off-design performance of gas turbines. Retrieved from: https://www.scribd.com/document/92384867/GasTurb9Manual. cited by applicant .
Tummers, B. (2006). DataThief III. Retreived from: https://datathief.org/DatathiefManual.pdf pp. 1-52. cited by applicant .
Manual. Student's Guide to Learning SolidWorks Software. Dassault Systemes--SolidWorks Corporation. pp. 1-156. cited by applicant .
Macisaac, B. and Langston, R. (2011). Gas turbine propulsion systems. Chichester, West Sussex: John Wiley & Sons, Ltd. pp. 260-265. cited by applicant .
Datasheet. CFM56-5B for the Airbus A320ceo family and CFM56-7B for the Boeing 737 family. https://www.cfmaeroengines.com/. cited by applicant .
Turner, M. G., Norris, A., and Veres, J.P. (2004). High-fidelity three-dimensional simulation of the GE90. NASA/TM-2004-212981. pp. 1-18. cited by applicant .
Defeo, A. and Kulina, M. (1977). Quiet clean short-haul experimental engine (QCSEE) main reduction gears detailed design final report. Prepared for NASA. NASA-CR-134872. Jul. 1977. pp. 1-221. cited by applicant .
Amezketa, M., Iriarte, X., Ros, J., and Pintor, J. (2009). Dynamic model of a helical gear pair with backlash and angle0varying mesh stiffness. Multibody Dynamics 2009, ECCOMAS Thematic Conference. 2009. pp. 1-36. cited by applicant .
Singh, A. (2005). Application of a system level model to study the planetary load sharing behavior. Jounal of Mechanical Design. vol. 127. May 2005. pp. 469-476. cited by applicant .
Smith-Boyd, L. and Pike, J. (1986). Expansion of epicyclic gear dynamic analysis program. Prepared for NASA. NASA CR-179563. Aug. 1986. pp. 1-98. cited by applicant .
Wikipedia. Torsion spring. Retreived Jun. 29, 2018 from: https://en.wikipedia.org/wiki/Torsion_spring. cited by applicant .
AGMA Standard (2006). Design manual for enclosed epicyclic gear drives. Alexandria, VA: American Gear Manufacturers Association. pp. 1-104. cited by applicant .
AGMA Standard (1997). Design and selection of components for enclosed gear drives. lexandria, VA: American Gear Manufacturers Association. pp. 1-48. cited by applicant .
Daly, M. Ed. (2007). Jane's Aero-Engine. Issue Twenty-three. Mar. 2008. p. 707-712. cited by applicant .
AGMA Standard (1999). Flexible couplings--Mass elastic properties and other characteristics. Alexandria, VA: American Gear Manufacturers Association. pp. 1-46. cited by applicant .
Wikipedia. Stiffness. Retrieved Jun. 28, 2018 from: https://en.wikipedia.org/wiki/Stiffness. cited by applicant .
Damerau, J. (2014) What is the mesh stiffness of gears? Screen shot of query submitted by Vahid Dabbagh, answered by Dr. Jochan Damerau, Research General Manager at Bosch Corp., Japan. Retrieved from: https://www.researchgate.net/post/What_is_the_mesh_stiffness_of_gears. cited by applicant .
Hill, P.G., Peterson, C.R. (1965). Mechanics and thermodynamics of propulsion. Addison-Wesley Publishing Company, Inc. pp. 307-308. cited by applicant .
Hill, P.G., Peterson, C.R. (1992). Mechanics and thermodynamics of propulsion, 2nd Edition. Addison-Wesley Publishing Company, Inc. pp. 400-406. cited by applicant .
Kasuba, R. and August, R. (1984). Gear mesh stiffness and load sharing in planetary gearing. American Society of Mechanical Engineers, Design Engineering Technical Conference, Cambridge, MA. Oct. 7-10, 1984. pp. 1-6. cited by applicant .
Ciepluch, C. (1977). Quiet clean short-haul experimental engine (QCSEE) under-the-wing (UTW) final design report. Prepared for NASA. NASA-CP-134847. Retreived from: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19800075257.pdf. cited by applicant .
Gray, D.E. and Gardner, W.B. (1983). Energy efficient engine program technology benefit/cost study--vol. 2. NASA CR-174766. Oct. 1983. pp. 1-118. cited by applicant .
Groweneweg, J.F. (1994). Fan noise research at NASA. NASA-TM-106512. Prepared for the 1994 National Conference on Noise Control Engineering. Fort Lauderdale, FL. May 1-4, 1994. pp. 1-10. cited by applicant .
Groweneweg, J.F. (1994). Fan noise research at NASA. Noise-CON 94. Fort Lauderdale, FL. May 1-4, 1994. pp. 1-10. cited by applicant .
Heidelberg, L.J., and Hall, D.G. (1992). Acoustic mode measurements in the inlet of a model turbofan using a continuously rotating rake. NASA-TM-105989. Prepared for the 31st Aerospace Sciences Meeting. Reno, NV. Jan. 11-14, 1993. pp. 1-30. cited by applicant .
Heidelberg, L.J., and Hall, D.G. (1992). Acoustic mode measurements in the inlet of a model turbofan using a continuously rotating rake. AIAA-93-0598. 31st Aerospace Sciences Meeting. Reno, NV. Jan. 11-14, 1993. pp. 1-30. cited by applicant .
Howe, D.C., and Wynosky, T.A. (1985). Energy efficient engine program advanced turbofan nacelle definition study. NASA-CR-174942. May 1985. pp. 1-60. cited by applicant .
Howe, D.C., and Wynosky, T.A. (1985). Energy efficient engine program advanced turbofan nacelle definition study. NASA-CR-174942. May 1985. University of Washington dated Dec. 13, 1990. pp. 1-14. cited by applicant .
Wie, Y.S., Collier, F.S., Wagner, R.D., Viken, J.K., and Pfenniger, W. (1992). Design of a hybrid laminar flow control engine nacelle. AIAA-92-0400. 30th Aerospace Sciences Meeting & Exhibit. Jan. 6-9, 1992. pp. 1-14. cited by applicant .
Mattingly, J.D. (1996). Elements of gas turbine propulsion. New York, New York: McGraw-Hill, Inc. pp. 1-18, 60-62, 223-234, 462-479, 517-520, 757-767, and 862-864. cited by applicant .
Johnston, R.P., Hirschkron, R., Koch, C.C., Neitzel, R.E., and Vinson, P.W. (1978). Energy efficient engine: Preliminary design and integration study-final report NASA CR-135444. Sep. 1978. pp. 1-401. cited by applicant .
Johnston, R.P. and Hemsworth, M.G. (1978). Energy efficient engine preliminary design and integration studies. Jun. 1, 1978. pp. 1-28. cited by applicant .
Awker, R.W. (1986). Evaluation of propfan propulsion applied to general aviation. NASA CR-175020. Mar. 1, 1986. pp. 1-140. cited by applicant .
Howe, D.C. and Wynosky, T.A. (1985). Energy efficient engine program advanced turbofan nacelle definition study. NASA CR-174942. May 1, 1985. pp. 174. cited by applicant .
Singh, B. (1986). Small engine component technology (SECT) study. NASA CR-175079. Mar. 1, 1986. pp. 1-102. cited by applicant .
Liebeck, R.H., Andrastek, D.A., Chau, J., Girvin, R., Lyon, R., Rawdon, B.K., Scott, P.W. et al. (1995). Advanced subsonic airplane design & economics studies. NASA CR-195443. Apr. 1995. pp. 1-187. cited by applicant .
McMillian, A. (2008) Material development for fan blade containment casing. Abstract. p. 1. Conference on Engineering and Physics: Synergy for Success 2006. Journal of Physics: Conference Series vol. 105. London, UK. Oct. 5, 2006. cited by applicant .
Kurzke, J. (2009). Fundamental differences between conventional and geared turbofans. Proceedings of ASME Turbo Expo: Power for Land, Sea, and Air. 2009, Orlando, Florida. pp. 145-151. cited by applicant .
Agarwal, B.D and Broutman, L.J. (1990). Analysis and performance of fiber composites, 2nd Edition. John Wiley & Sons, Inc. New York: New York. pp. 1-30, 50-1, 56-8, 60-1, 64-71, 87-9, 324-9, 436-7. cited by applicant .
Carney, K., Pereira, M. Revilock, and Matheny, P. (2003). Jet engine fan blade containment using two alternate geometries. 4th European LS-DYNA Users Conference. pp. 1-10. cited by applicant .
Brines, G.L. (1990). The turbofan of tomorrow. Mechanical Engineering: The Journal of the American Society of Mechanical Engineers,108(8), 65-67. cited by applicant .
Faghri, A. (1995). Heat pipe and science technology. Washington, D.C.: Taylor & Francis. pp. 1-60. cited by applicant .
Hess, C. (1998). Pratt & Whitney develops geared turbofan. Flug Revue 43(7). Oct. 1998. cited by applicant .
Grady, J.E., Weir, D.S., Lamoureux, M.C., and Martinez, M.M. (2007). Engine noise research in NASA's quiet aircraft technology project. Papers from the International Symposium on Air Breathing Engines (ISABE). 2007. cited by applicant .
Griffiths, B. (2005). Composite fan blade containment case. Modern Machine Shop. Retrieved from: http://www.mmsonline.com/articles/composite-fan-blade-containment-case pp. 1-4. cited by applicant .
Hall, C.A. and Crichton, D. (2007). Engine design studies for a silent aircraft. Journal of Turbomachinery, 129, 479-487. cited by applicant .
Haque, A. and Shamsuzzoha, M., Hussain, F., and Dean, D. (2003). S20-glass/epoxy polymer nanocomposites: Manufacturing, structures, thermal and mechanical properties. Journal of Composite Materials, 37(20), 1821-1837. cited by applicant .
Brennan, P.J. and Kroliczek, E.J. (1979). Heat pipe design handbook. Prepared for National Aeronautics and Space Administration by B & K Engineering, Inc. Jun. 1979. pp. 1-348. cited by applicant .
Horikoshi, S. and Serpone, N. (2013). Introduction to nanoparticles. Microwaves in nanoparticle synthesis. Wiley-VCH Verlag GmbH & Co. KGaA. pp. 1-24. cited by applicant .
Kerrebrock, J.L. (1977). Aircraft engines and gas turbines. Cambridge, MA: The MIT Press. p. 11. cited by applicant .
Xie, M. (2008). Intelligent engine systems: Smart case system. NASA/CR-2008-215233. pp. 1-31. cited by applicant .
Knip, Jr., G. (1987). Analysis of an advanced technology subsonic turbofan incorporating revolutionary materials. NASA Technical Memorandum. May 1987. pp. 1-23. cited by applicant .
Willis, W.S. (1979). Quiet clean short-haul experimental engine (QCSEE) final report NASA/CR-159473 pp. 1-289. cited by applicant .
Kojima, Y., Usuki, A. Kawasumi, M., Okada, A., Fukushim, Y., Kurauchi, T., and Kamigaito, O. (1992). Mechanical properties of nylon 6-clay hybrid. Journal of Materials Research, 8(5), 1185-1189. cited by applicant .
Kollar, L.P. and Springer, G.S. (2003). Mechanics of composite structures. Cambridge, UK: Cambridge University Press. p. 465. cited by applicant .
Ramsden, J.M. (Ed). (1978). The new European airliner. Flight International, 113(3590). Jan. 7, 1978. pp. 39-43. cited by applicant .
Langston, L. and Faghri, A. Heat pipe turbine vane cooling. Prepared for Advanced Turbine Systems Annual Program Review. Morgantown, West Virginia. Oct. 17-19, 1995. pp. 3-9. cited by applicant .
Oates, G.C. (Ed). (1989). Aircraft propulsion systems and technology and design. Washington, D.C.: American Institute of Aeronautics, Inc. pp. 341-344. cited by applicant .
Lau, K., Gu, C., and Hui, D. (2005). A critical review on nanotube and nanotube/nanoclay related polymer composite materials. Composites: Part B 37(2006) 425-436. cited by applicant .
Shorter Oxford English dictionary, 6th Edition. (2007). vol. 2, N-Z. p. 1888. cited by applicant .
Lynwander, P. (1983). Gear drive systems: Design and application. New York, New York: Marcel Dekker, Inc. pp. 145, 355-358. cited by applicant .
Sweetman, B. and Sutton, O. (1998). Pratt & Whitney's surprise leap. Interavia Business & Technology, 53.621, p. 25. cited by applicant .
Mattingly, J.D. (1996). Elements of gas turbine propulsion. New York, New York: McGraw-Hill, Inc. pp. 8-15. cited by applicant .
Pyrograf-III Carbon Nanofiber. Product guide. Retrieved Dec. 1, 2015 from: http://pyrografproducts.com/Merchant5/merchant_mvc?Screen=cp_nanofiber. cited by applicant .
Nanocor Technical Data for Epoxy Nanocomposites using Nanomer 1.30E Nanoclay. Nnacor, Inc. Oct. 2004. cited by applicant .
Ratna, D. (2009). Handbook of thermoset resins. Shawbury, UK: iSmithers. pp. 187-216. cited by applicant .
Wendus, B.E., Stark, D.F., Holler, R.P., and Funkhouser, M.E. (2003). Follow-on technology requirement study for advanced subsonic transport NASA/CR-2003-212467. pp. 1-37. cited by applicant .
Silverstein, C.C., Gottschlich, J.M., and Meininger, M. The feasibility of heat pipe turbine vane cooling. Presented at the International Gas Turbine and Aeroengine Congress and Exposition, The Hague, Netherlands. Jun. 13-16, 1994.pp. 1-7. cited by applicant .
Merriam-Webster's collegiate dictionary, 11th Ed. (2009). p. 824. cited by applicant .
Merriam-Webster's collegiate dictionary, 10th Ed. (2001). p. 1125-1126. cited by applicant .
Whitaker, R. (1982). ALF 502: plugging the turbofan gap. Flight International, p. 237-241, Jan. 30, 1982. cited by applicant .
Hughes, C. (2010). Geared turbofan technology. NASA Environmentally Responsible Aviation Project. Green Aviation Summit. NASA Ames Research Center. Sep. 8-9, 2010. pp. 1-8. cited by applicant .
Gliebe, P.R. and Janardan, B.A. (2003). Ultra-high bypass engine aeroacoustic study. NASA/CR-2003-21252. GE Aircraft Engines, Cincinnati, Ohio. Oct. 2003. pp. 1-103. cited by applicant .
Moxon, J. How to save fuel in tomorrow's engines. Flight International. Jul. 30, 1983. 3873(124). pp. 272-273. cited by applicant .
File History for U.S. Appl. No. 12/131,876. cited by applicant .
Cusick, M. (1981). Avco Lycoming's ALF 502 high bypass fan engine. Society of Automotive Engineers, inc. Business Aircraft Meeting & Exposition. Wichita, Kansas. Apr. 7-10, 1981. pp. 1-9. cited by applicant .
Fledderjohn, K.R. (1983). The TFE731-5: Evolution of a decade of business jet service. SAE Technical Paper Series. Business Aircraft Meeting & Exposition. Wichita, Kansas. Apr. 12-15, 1983. pp. 1-12. cited by applicant .
Dickey, T.A. and Dobak, E.R. (1972). The evolution and development status of ALF 502 turbofan engine. National Aerospace Engineering and Manufacturing Meeting. San Diego, California. Oct. 2-5, 1972. pp. 1-12. cited by applicant .
Gunston, B. (Ed.) (2000). Jane's aero-engines, Issue seven. Coulsdon, Surrey, UK: Jane's Information Group Limited. pp. 510-512. cited by applicant .
Ivchenko-Progress D-436. Jane's Aero-engines, Aero-engines--Turbofan. Feb. 8, 2012. cited by applicant .
Ivchenko-Progress AI-727M. Jane's Aero-engines, Aero-engines--Turbofan. Nov. 27, 2011. cited by applicant .
Ivchenko-Progress D-727. Jane's Aero-engines, Aero-engines--Turbofan. Feb. 7, 2007. cited by applicant .
Turbomeca Aubisque. Jane's Aero-engines, Aero-engines--Turbofan. Nov. 2, 2009. cited by applicant .
Aviadvigatel D-110. Jane's Aero-engines, Aero-engines--Turbofan. Jun. 1, 2010. cited by applicant .
Rolls-Royce M45H. Jane's Aero-engines, Aero-engines--Turbofan. Feb. 24, 2010. cited by applicant .
Honeywell LF502. Jane's Aero-engines, Aero-engines--Turbofan. Feb. 9, 2012. cited by applicant .
Anderson, R.D. (1985). Advanced Propfan Engine Technology (APET) definition study, single and counter-rotation gearbox/pitch change mechanism design. NASA CR-168115. Jul. 1, 1985. pp. 1-289. cited by applicant .
Newton, F.C., Liebeck, R.H., Mitchell, G.H., Mooiweer, M.A., Platte, M.M., Toogood, T.L., and Wright, R.A. (1986). Multiple Application Propfan Study (MAPS): Advanced tactical transport. NASA CR-175003. Mar. 1, 2986. pp. 1-101. cited by applicant .
Gliebe, P.R., Ho, P.Y., and Mani, R. (1995). UHB engine fan and broadband noise reduction study. NASA CR-198357. Jun. 1995. pp. 1-48. cited by applicant .
Holcombe, V. (2003). Aero-Propulsion Technology (APT) task V low noise ADP engine definition study. NASA CR-2003-212521. Oct. 1, 2003. pp. 1-73. cited by applicant .
Sutliff, D. (2005). Rotating rake turbofan duct mode measurement system. NASA TM-2005-213828. Oct. 1, 2005. pp. 1-34. cited by applicant .
Adamson, A.P. (1975). Quiet Clean Short-Haul Experimental Engine (QCSEE) design rationale. Society of Automotive Engineers. Air Transportation Meeting. Hartford, CT. May 6-8 1975. pp. 1-9. cited by applicant .
NASA Conference Publication. (1978). CTOL transport technology. NASA-CP-2036-PT-1. Jun. 1, 1978. pp. 1-531. cited by applicant .
Kandebo, S.W. (1998). Geared-Turbofan engine design targets cost, complexity. Aviation Week & Space Technology, 148(8). p. 34-35. cited by applicant .
Davis, D.G.M. (1973). Variable-pitch fans: Progress in Britain. Flight International. Apr. 19, 1973. pp. 615-617. cited by applicant .
Levintan, R.M. (1975). Q-Fan demonstrator engine. Journal of Aircraft. vol. 12( 8). Aug. 1975. pp. 658-663. cited by applicant .
Technical Report. (1975). Quiet Clean Short-haul Experimental Engine (QCSEE) UTW fan preliminary design. NASA-CR-134842. Feb. 1, 1975. pp. 1-98. cited by applicant .
Aerospace Information Report. (2008). Advanced ducted propulsor in-flight thrust determination. SAE International AIR5450. Aug. 2008. p. 1-392. cited by applicant .
Daggett, D.L., Brown, S.T., and Kawai, R.T. (2003). Ultra-efficient engine diameter study. NASA/CR-2003-212309. May 2003. pp. 1-52. cited by applicant .
Davies, D. and Miller, D.C. (1971). A variable pitch fan for an ultra quiet demonstrator engine. 1976 Spring Convention: Seeds for Success in Civil Aircraft Design in the Next Two Decades. pp. 1-18. cited by applicant .
Middleton, P. (1971). 614: VFW's jet feederliner. Flight International, Nov. 4, 1971. p. 725, 729-732. cited by applicant .
Schaefer, J.W., Sagerser, D.R., and Stakolich, E.G. (1977). Dynamics of high-bypass-engine thrust reversal using a variable-pitch fan. Technical Report prepare for NASA. NASA-TM-X-3524. May 1, 1977. pp. 1-31. cited by applicant .
Savelle, S.A. and Garrard, G.D. (1996). Application of transient and dynamic simulations to the U.S. Army T55-L-712 helicopter engine. The American Society of Mechanical Engineers. Presented Jun. 10-13, 1996. pp. 1-8. cited by applicant .
Drago, R.J. and Margasahayam, R.N. (1987). Stress analysis of planet gears with integral bearings; 3D finite-element model development and test validation. 1987 MSC NASTRAN World Users Conference. Los Angeles, CA. Mar. 1987. pp. 1-14. cited by applicant .
Baker, R.W. (2000). Membrane technology and applications. New York, NY: McGraw-Hill. pp. 87-151. cited by applicant .
Cheryan, M. (1998). Ultrafiltration and microfiltration handbook. Lancaster, PA: Tecnomic Publishing Company, Inc. pp. 171-236. cited by applicant .
Seader, J.D. and Henley, E.J. (1998). Separation process principles. New York, NY: John Wiley & Sons, Inc. pp. 722-726 and 764-771. cited by applicant .
Spadaccini, L.J., and Huang, H. (2002). On-line fuel deoxygenation for coke suppression. ASME, Jun. 2002. pp. 1-7. cited by applicant .
Darrah, S. (1987). Jet fuel deoxygenation. Interim Report for Period Mar. 1987-Jul. 1988. pp. 1-22. cited by applicant .
Bucknell, R.L. (1973). Influence of fuels and lubricants on turbine engine design and performance, fuel and lubricant analyses. Final Technical Report, Mar. 1971-Mar. 1973. pp. 1-252. cited by applicant .
Hazlett, R.N. (1991). Thermal oxidation stability of aviation turbine fuels. Philadelphia, PA: ASTM. pp. 1-163. cited by applicant .
Taylor, W.F. (1974). Deposit formation from deoxygenated hydrocarbons. I. General features. Ind. Eng. Chem., Prod. Res. Develop., vol. 13(2). 1974. pp. 133-138. cited by applicant .
Taylor, W.F. (1974). Deposit formation from deoxygenated hydrocarbons. II. Effect of trace sulfur compounds. Ind. Eng. Chem., Prod. Res. Dev., vol. 15(1). 1974. pp. 64-68. cited by applicant .
Taylor, W.F. and Frankenfeld, J.W. (1978). Deposit fromation from deoxygenated hydrocarbons. 3. Effects of trace nitrogen and oxygen compounds. Ind. Eng. Chem., Prod. Res. Dev., vol. 17(1). 1978. pp. 86-90. cited by applicant .
Frankenfeld, J.W. and Taylor, W.F. (1980). Deposit fromation from deoxygenated hydrocarbons. 4. Studies in pure compound systems. Ind. Eng. Chem., Prod. Res. Dev., vol. 19(1). 1978. pp. 65-70. cited by applicant .
Hemighaus, G., Boval, T., Bacha, J., Barnes, F., Franklin, M., Gibbs, L., . . . Morris, J. (2007). Aviation fuels: Technical review. Chevron Products Company. pp. 1-94. Retrieved from: https://www.cgabusinessdesk.com/document/aviation_tech_review.pdf. cited by applicant .
Spadaccini, L.J., Sobel, D.R., and Huang, H. (2001). Deposit formation and mitigation in aircraft fuels. Journal of Eng. For Gas Turbine and Power, vol. 123. Oct. 2001. pp. 741-746. cited by applicant .
Edwards, T. and Zabarnick, S. (1993). Supercritical fuel deposition mechanisms. Ind. Eng. Chem. Res. vol. 32. 1993. pp. 3117-3122. cited by applicant .
Huang, H., Sobel, D.R., and Spadaccini, L.J. (2002). Endothermic heat-sink of hydrocarbon fuels for scramjet cooling. AIAA/ASME/SAE/ASEE, Jul. 2002. pp. 1-7. cited by applicant .
Bessarabov, D.G., Jacobs, E.P., Sanderson, R.D., and Beckman, I.N. (1996). Use of nonporous polymeric flat-sheet gas-separation membranes in a membrane-liquid contactor: experimental studies. Journal of Membrane Sciences, vol. 113. 1996. pp. 275-284. cited by applicant .
Matsumoto, T., Toshiro, U., Kishida, A., Tsutomu, F., Maruyama, I., and Akashi, M. (1996). Novel functional polymers: Poly (dimethylsiloxane)-polyamide multiblock copolymer. VII. Oxygen permeability of aramid-silicone membranes in a gas-membrane-liquid system. Journal of Applied Polymer Science, vol. 64(6). May 9, 1997. pp. 1153-1159. cited by applicant .
Technical Data. Teflon. WS Hampshire Inc. Retrieved from: http://catalog.wshampshire.com/Asset/psg_teflon_ptfe.pdf. cited by applicant .
Anderson, N.E., Loewenthal, S.H., and Black, J.D. (1984). An analytical method to predict efficiency of aircraft gearboxes. NASA Technical Memorandum prepared for the Twentieth Joint Propulsion Conference. Cincinnati, OH. Jun. 11-13, 1984. pp. 1-25. cited by applicant .
Edkins, D.P., Hirschkron, R., and Lee, R. (1972). TF34 turbofan quiet engine study. Final Report prepared for NASA. NASA-CR-120914. Jan. 1, 1972. pp. 1-99. cited by applicant .
Waters, M.N. and Schairer, E.T. (1977). Analysis of turbofan propulsion system weight and dimensions. NASA Technical Memorandum. Jan. 1977. pp. 1-65. cited by applicant .
Meyer, A.G. (1988). Transmission development of TEXTRON Lycoming's geared fan engine. Technical Paper. Oct. 1988. pp. 1-12. cited by applicant .
Dudley, D.W., Ed. (1962). Gear handbook. New York, NY: McGraw-Hill. pp. 14-17 (TOC, Preface, and Index). cited by applicant .
Hughes, C. (2002). Aerodynamic performance of scale-model turbofan outlet guide vanes designed for low noise. Prepared for the 40th Aerospace Sciences Meeting and Exhibit. Reno, NV. NASA/TM-2001-211352. Jan. 14-17, 2002. pp. 1-38. cited by applicant .
Kaplan, B., Nicke, E., Voss, C. (2006), Design of a highly efficient low-noise fan for ultra-high bypass engines. Proceedings of GT2006 for ASME Turbo Expo 2006: Power for Land, Sea and Air. Barcelona, SP. May 8-11, 2006. pp. 1-10. cited by applicant .
Gates, D. Bombardier flies at higher market. Seattle Times. Jul. 13, 2008. pp. C6. cited by applicant .
Decker, S. and Clough, R. (2016). GE wins shot at voiding pratt patent in jet-engine clash. Bloomberg Technology. Retrieved from: https://www.bloomberg.com/news/articles/2016-06-30/ge-wins-shot-to-invali- date-pratt-airplane-engine-patent-in-u-s. cited by applicant .
Trembley, Jr., H.F. (1977). Determination of effects of ambient conditions on aircraft engine emissions. ALF 502 combustor rig testing and engine verification test. Prepared for Environmental Protection Agency. Sep. 1977. pp. 1-256. cited by applicant .
Lewicki, D.G., Black, J.D., Savage, M., and Coy, J.J. (1985). Fatigue life analysis of a turboprop reduction gearbox. NASA Technical Memorandum. Prepared for the Design Technical Conference (ASME). Sep. 11-13, 1985. pp. 1-26. cited by applicant .
McCune, M.E. (1993). Initial test results of 40,000 horsepower fan drive gear system for advanced ducted propulsion systems. AIAA 29th Joint Conference and Exhibit. Jun. 28-30, 1993. pp. 1-10. cited by applicant .
Wright, G.H. and Russell, J.G. (1990). The M.45SD-02 variable pitch geared fan engine demonstrator test and evaluation experience. Aeronautical Journal., vol. 84(836). Sep. 1980. pp. 268-277. cited by applicant .
Drago, R.J. (1974). Heavy-lift helicopter brings up drive ideas. Power Transmission Design. Mar. 1987. pp. 1-15. cited by applicant .
Krantz, T.L. (1990). Experimental and analytical evaluation of efficiency of helicopter planetary stage. NASA Technical Paper. Nov. 1990. pp. 1-19. cited by applicant .
Heingartner, P., MBA, D., Brown, D. (2003). Determining power losses in the helical gear mesh; Case Study. ASME 2003 Design Engineering Technical Conferences. Chicago, IL. Sep. 2-6, 2003. pp. 1-7. cited by applicant .
Thulin, R.D., Howe, D.C., and Singer, I.D. (1982). Energy efficient engine: High pressure turbine detailed design report. Prepared for NASA. NASA CR-165608. Received Aug. 9, 1984. pp. 1-178. cited by applicant .
Reshotko, M., Karchmer, A., Penko, P.F. (1977). Core noise measurements on a YF-102 turbofan engine. NASA TM X-73587. Prepared for Aerospace Sciences Meeting sponsored by the American Institute of Aeronautics and Astronautics. Jan. 24-26, 2977. cited by applicant .
Gray, D.E. (1978). Energy efficient engine preliminary design and integration studies. Prepared for NASA. NASA CR-135396. Nov. 1978. pp. 1-366. cited by applicant .
Reynolds, C.N. (1985). Advanced prop-fan engine technology (APET) single- and counter-rotation gearbox/pitch change mechanism. Prepared for NASA. NASA CR-168114 (vol. I). Jul. 1985. pp. 1-295. cited by applicant .
McArdle, J.G. and Moore, A.S. (1979). Static test-stand performance of the YF-102 turobfan engine with several exhaust configurations for the Quiet Short-Haul Research Aircraft (QSRA). Prepared for NASA. NASA-TP-1556. Nov. 1979. pp. 1-68. cited by applicant .
Mattingly, J.D. (1996). Elements of gas turbine propulsion. New York, New York: McGraw-Hill, Inc. pp. 1-18, 60-62, 85-87, 95-104, 121-123, 223-234, 242-245, 278-285, 303-309, 323-326, 462-479, 517-520, 563-565, 630-632, 668-670, 673-675, 682-685, 697-705, 726-727, 731-732, 802-805, 828-830 and appendices. cited by applicant .
Falchetti, F., Quiniou, H., and Verdier, L. (1994). Aerodynamic design and 3D Navier-Stokes analysis of a high specific flow fan. ASME. Presented at the International Gas Turbine and Aeroengine Congress and Exposition. The Hague, Netherlands. Jun. 13-16, 1994. pp. 1-10. cited by applicant .
Datasheet. CF6-80C2 high-bypass turbofan engines. Retreived from https://geaviation.com/sites/default/files/datasheet-CF6-80C2.pdf. cited by applicant .
Salemme, C.T. and Murphy, G.C. (1979). Metal spar/superhybrid shell composite fan blades. Prepared for NASA. NASA-CR-159594. Aug. 1979. pp. 1-127. cited by applicant .
"Press release. The GE90 engine. Retreived from: https://www.geaviation.com/commercial/engines/ge90-engine; https://www.geaviation.com/press-release/ge90-engine-family/ge90-115b-fan- -completing-blade-testing-schedule-first-engine-test; and https://www.geaviation.com/press-release/ge90-engine-family/ge'scomposite- -fan-blade-revolution-turns-20-years-old". cited by applicant .
Datasheet. Genx.TM. high bypass turbofan engines. Retreived from: https://www.geaviation.com/sites/default/files/datasheet-genx.pdf. cited by applicant .
Bloomer, H.E., Loeffler, I.J., Kreim, W.J., and Coats, J.W. (1981). Comparison of NASA and contractor resits from aeroacoustic tests of QCSEE OTW engine. NASA Technical Memorandum 81761. Apr. 1, 1981. pp. 1-30. cited by applicant .
Bloomer, H.E. and Samanich, N.E. (1982). QCSEE under-the-wing engine acoustic data. NASA-TM-82691. May 1, 1982. pp. 1-28. cited by applicant .
Bloomer, H.E. and Loeffler, I.J. (1982). QCSEE over-the-wing engine acoustic data. NASA-TM-82708. May 1, 1982. pp. 1-558. cited by applicant .
Bloomer, H.E. and Samanich, N.E. (1982). QCSEE under-the-wing enging-wing-flap aerodynamic profile characteristics. NASA-TM-82890. Sep. 1, 1982. pp. 1-48. cited by applicant .
Howard, D.F. (1976). QCSEE preliminary under the wing flight propulsion system analysis report. NASA CR-134868. Feb. 1, 1976. pp. 1-260. cited by applicant .
Misel, O.W. (1977). QCSEE main reduction gears test program. NASA CR-134669. Mar. 1, 1977. pp. 1-222. cited by applicant .
QCSEE Preliminary analyses and design report. Volume 1. (1974). NASA-CR-134838. Oct. 1, 1974. pp. 1-337. cited by applicant .
QCSEE preliminary analyses and design report vol. II. (1974). NASA-CR-134839. Oct. 1, 1974. pp. 340-630. cited by applicant .
QCSEE under-the-wing engine composite fan blade design. (1975). NASA-CR-134840. May 1, 1975. pp. 1-51. cited by applicant .
QCSEE the aerodynamic and preliminary mechanical design of the QCSEE OTW fan. (1975). NASA-CR-134841. Feb. 1, 1975. pp. 1-74. cited by applicant .
QCSEE under-the-wing engine composite fan blade preliminary design test report. (1975). NASA-CR-134846. Sep. 1, 1975. pp. 1-56. cited by applicant .
QCSEE over-the-wing final design report. (1977). NASA-CR-134848. Jun. 1, 1977. pp. 1-503. cited by applicant .
QCSEE hamilton standard cam/harmonic drive variable pitch fan actuation system derail design report. (1976). NASA-CR-134852. Mar. 1, 1976. pp. 1-172. cited by applicant .
QCSEE main reduction gears bearing development program final report. (1975). NASA-CR-134890. Dec. 1, 1975. pp. 1-41. cited by applicant .
QCSEE under-the-wing engine digital control system design report. (1978). NASA-CR-134920. Jan. 1, 1978. pp. 1-309. cited by applicant .
QCSEE the aerodynamic and mechanical design of the QCSEE under-the-wing fan. (1977). NASA-CR-135009. Mar. 1, 1977. pp. 1-137. cited by applicant .
QCSEE under-the-wing engine composite fan blade final design test report. (1977). NASA-CR-135046. Feb. 1, 1977. pp. 1-55. cited by applicant .
QCSEE over-the-wing propulsion system test report vol. III--mechanical performance. (1978). NASA-CR-135325. Feb. 1, 1978. pp. 1-112. cited by applicant .
QCSEE ball spline pitch-change mechanism whirligig test report (1978). NASA-CR-135354. Sep. 1, 1978. pp. 1-57. cited by applicant .
Quiet clean general aviation turbofan (QCGAT) technology study final report vol. I. (1975). NASA-CR-164222. Dec. 1, 1975. pp. 1-186. cited by applicant .
Neitzel, R.E, Hirschkron, R. and Johnston, R.P. (1976). Study of unconventional aircraft engines designed for low energy consumption. NASA-CR-135136. Dec. 1, 1976. pp. 1-153. cited by applicant .
Neitzel, R., Lee, R., and Chamay, A.J. (1973). Engine and installation preliminary design. Jun. 1, 1973. pp. 1-333. cited by applicant .
Parametric study of STOL short-haul transport engine cycles and operational techniques to minimize community noise impact. NASA-CR-114759. Jun. 1, 1974. pp. 1-398. cited by applicant .
Sowers, H.D. and Coward, W.E. (1978). QCSEE over-the-wing (OTW) engine acuostic design. NASA-CR-135268. Jun. 1, 1978. pp. 1-52. cited by applicant .
Schaefer, J.W., Sagerser, D.R., and Stakolich, E.G. (1977). Dynamics of high-bypass-engine thrust reversal using a variable-pitch fan. Technical Report prepared for NASA. NASA-TM-X-3524. May 1, 1977. pp. 1-33. cited by applicant .
U.S. Appl. No. 11/832,107, dated Aug. 1, 2007, Engine Mounting Configuration for a Turbofan Gas Turbine Engine. cited by applicant .
Article--"Gas Power Cycle--Jet Propulsion Technology, a Case Study," from MachineDesign.com website. cited by applicant .
International Search Report and Written Opinion for PCT Application No. PCT/US2012/072271 dated Mar. 8, 2013. cited by applicant .
International Search Report and Written Opinion for International Application No. PCT/US2014/57127 dated Jun. 10, 2015. cited by applicant .
International Preliminary Report on Patentability for International Application No. PCT/US2014/057127 dated Apr. 28, 2016. cited by applicant .
European Search Report for EP Application No. 14870182.4 dated May 26, 2017. cited by applicant .
Gray, D.E. (1978). Energy efficient engine preliminary design and integration studies. NASA-CP-2036-PT-1. Nov. 1978. pp. 89-110. cited by applicant .
Kandebo, S.W. (1993). Pratt & Whitney launches geared turbofan engine. Aviation Week & Space Technology, 148(8). p. 32-34. cited by applicant .
Kandebo, S.W. (1993). Geared-Turbofan engine design targets cost, complexity. Aviation Week & Space Technology, 148(8). p. 34-35. cited by applicant .
Technical Report. (1975). Quiet Clean Short-haul Experimental Engine (QCSEE) Under-the-Wing (UTW) final design report. NASA-CR-134847. Jun. 1, 1977. pp. 1-697. cited by applicant .
2003 NASA seal/secondary air system workshop. (2003). NASA/CP-2004-212963/VOL1. Sep. 1, 2004. pp. 1-408. cited by applicant .
Berton, J.J. and Guynn, M.D. (2012). Multi-objective optimization of a turbofan for an advanced, single-aisle transport. NASA/TM-2012-217428. pp. 1-26. cited by applicant .
Chapman, J.W. and Litt, J.S. (2017). Control design for an advanced geared turbofan engine. AIAA Joint Propulsion Conference 2017. Jul. 10, 2017-Jul. 12, 2017. Atlanta, GA. pp. 1-12. cited by applicant .
Dalton, III., W.N. (2003). Ultra high bypass ratio low noise engine study. NASA/CR-2003-212523. Nov. 2003. pp. 1-187. cited by applicant .
Fisher, K., Berton, J., Guynn, M., Haller B., Thurman, D., and Tong, M. (2012). NASA's turbofan engine concept study for a next-generation single-aisle transport Presentation to ICAO's noise technology independent expert panel. Jan. 25, 2012. pp. 1-23. cited by applicant .
Greitzer, E.M., Bonnefoy, P.A., Delaroseblanco,E., Dorbian, C.S., Drela, M., Hall, D.K., Hansman, R.J., Hileman, J.I., Liebeck, R.H., Levegren, J. (2010). N'aircraft concept designs and trade studies, final report. vol. 1. Dec. 1, 2010. NASA/CR-2010-216794/VOL1. pp. 1-187. cited by applicant .
Guynn, M.D., Berton, J.J., Fisher, K.L., Haller, W.J., Tong, M.T., and Thurman, D.R. (2009). Engine concept study for an advanced single-aisle transport. NASA/TM-2009-215784. pp. 1-97. cited by applicant .
Guynn, D.N., Berton, J.J., Fisher, K.L., Haller, W.J., Tong, M. T., and Thurman, D.R. (2009). Analysis of turbofan design options for an advanced single-aisle transport aircraft. American Institute of Aeronautics and Astronautics. pp. 1-13. cited by applicant .
Mavris, D.N., Schutte, J.S. (2016). Application of deterministic and probabilistic system design methods and enhancements of conceptual design tools for ERA project final report. NASA/CR-2016-219201. May 1, 2016. pp. 1-240. cited by applicant .
McCracken, R.C. (1979). Quiet short-haul research aircraft familiarization document. NASA-TM-81149. Nov. 1, 1979. pp. 1-76. cited by applicant .
Litt, J.S. (2018). Sixth NASA Glenn Research Center propulsion control and diagnostics (PCD) workshop. NASA/CP-2018-219891. Apr. 1, 2018. pp. 1-403. cited by applicant .
Rotordynamic instability problems in high-performance turbomachinery. (1986). NASA conference publication 2443. Jun. 2-4, 1986. cited by applicant .
Sargisson, D.F. (1985). Advanced propfan engine technology (APET) and single-rotation gearbox/pitch change mechanism. NASA Contractor Report--168113. R83AEB592. Jun. 1, 1985. pp. 1-476. cited by applicant .
Singh, R. and Houser, D.R. (1990). Non-linear dynamic analysis of geared systems. NASA-CR-180495. Feb. 1, 1990. pp. 1-263. cited by applicant .
Smith, C.E., Hirschkron, R., and Warren, R.E. (1981). Propulsion system study for small transport aircraft technology (STAT). Final report. NASA-CR-165330. May 1, 1981. pp. 1-216. cited by applicant .
Tong, M.T., Jones, S.M., Haller, W.J., and Handschuh, R.F. (2009). Engine conceptual design studies for a hybrid wing body aircraft. NASA/TM-2009-215680. Nov. 1, 2009. pp. 1-15. cited by applicant.

Primary Examiner: Davis; Mary
Attorney, Agent or Firm: Carlson, Gaskey & Olds, P.C.
Parent Case Text


CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No. 14/651,923 filed on Jun. 12, 2015, which is a National Phase Application of International Application No. PCT/US2014/057127 filed on Sep. 24, 2014, which claims priority to U.S. Provisional Application No. 61/891,475 filed on Oct. 16, 2013.
Claims


What is claimed is:

1. A turbofan engine comprising; a fan section including a fan blade having a leading edge and a hub to tip ratio of less than 0.34 and greater than 0.020 measured at the leading edge; a speed change system with a gear ratio greater than 2.6 to 1; a first compression section including a last blade trailing edge radial tip length that is greater than 67% of a radial tip length of a leading edge of a first stage of the first compression section; and a second compression section including a last blade trailing edge radial tip length that is greater than 57% of the radial tip length of the leading edge of the first stage of the second compression section; a turbine section including a fan drive turbine section and at least two turbine stages forward of a first turbine blade of the fan drive turbine section; and a mid-turbine frame disposed between the fan drive turbine and the at least two turbine stages for guiding core flow into the fan drive turbine, the mid-turbine frame supporting a bearing system for one of the fan drive turbine and the at least two turbine stages.

2. The turbofan engine as recited in claim 1, wherein the fan section provides a low fan pressure ratio less than 1.6.

3. The turbofan engine as recited in claim 2, wherein the fan section provides a low fan pressure ratio between 1.45 and 1.20.

4. The turbofan engine as recited in claim 3, wherein the fan section provides a bypass ratio greater than 8.

5. The turbofan engine as recited in claim 4, wherein the fan section provides a bypass ratio greater than 12.

6. The turbofan engine as recited in claim 5, wherein the fan drive turbine includes at least three stages.

7. The turbofan engine as recited in claim 6, wherein the fan drive turbine is coupled to drive the first compression section.

8. The turbofan engine as recited in claim 7, wherein at least one of the at least two turbine stages is coupled to drive the second compression section.

9. The turbofan engine as recited in claim 8, wherein the at least two stages comprises a two stage turbine forward of the fan drive turbine.

10. The turbofan engine as recited in claim 9, wherein the fan drive turbine comprises a turbine with from three to six stages.

11. The turbofan engine as recited in claim 10, wherein the fan section includes a plurality of fan blades and a ratio between a number of the plurality of fan blades and a number of stages of the fan drive turbine is between 3.3 and 8.6.

12. A turbofan engine comprising: a fan section providing a bypass ratio greater than 8, the fan section includes a plurality of fan blades supported on a hub, wherein at least one of the plurality of fan blades includes a leading edge and a hub to tip ratio is less than 0.34 and greater than 0.020 measured at the leading edge; a speed change system coupled to the hub with a gear ratio greater than 2.6 to 1; a first compression section including a last blade trailing edge tip length that is greater than 67% of the radial length of a first stage leading edge of the first compression section, wherein the first compression section operates at an efficiency of at least 0.84; a turbine section including a fan drive turbine section coupled to the speed change system and at least two turbine stages forward of a first turbine blade of the fan drive turbine section.

13. The turbofan engine as recited in claim 12, including a mid-turbine frame disposed between the fan drive turbine and the at least two turbine stages for guiding core flow into the fan drive turbine, the mid-turbine frame supporting a bearing system for one of the fan drive turbine and the at least two turbine stages.

14. A turbofan engine as recited in claim 13, including an eight stage second compression section including a last blade with a trailing edge tip that includes a radial length that is greater than 57% of a radial length of the first stage leading edge of the second compression section.

15. The turbofan engine as recited in claim 14, wherein the at least two stages comprise a second turbine section forward of the fan drive turbine.

16. The turbofan engine as recited in claim 12, including a second compression section that operates at an efficiency of at least 0.82.

17. The turbofan engine as recited in claim 16, wherein the fan drive turbine operates at an efficiency of at least 0.89 and the at least two turbine stages forward of the fan drive turbine section comprises a second turbine section operating at an efficiency of at least 0.85.

18. The turbofan engine as recited in claim 17, wherein the fan section includes a fan case circumscribing the plurality of fan blades and defining a bypass flow path.

19. The turbofan engine as recited in claim 18, wherein the fan drive turbine includes a plurality of rotor stages and a ratio between the number of the plurality of fan blades and the number of the plurality of rotor stages is between 3.3 and 8.6.

20. A turbofan engine comprising: a fan section providing a bypass ratio greater than 8, the fan section includes a plurality of fan blades supported on a hub, wherein at least one of the plurality of fan blades includes a leading edge and a hub to tip ratio is less than 0.34 and greater than 0.020 measured at the leading edge; a speed change system with gear ratio greater than 2.6 to 1; a three-stage first compression section disposed aft of the speed change system, the three-stage first compression section including a first rotating compressor blade with a leading edge and a last rotating compressor blade with a trailing edge, wherein a radial distance from an engine longitudinal axis to a tip of the trailing edge of the last rotating compressor blade is greater than 67% of a radial distance from the engine longitudinal axis to a tip of the first rotating compressor blade at the leading edge; a turbine section including a fan drive turbine section and a two stage turbine section forward of a first turbine blade of the fan drive turbine section, wherein the fan drive turbine operates at an efficiency of at least 0.89.

21. The turbofan engine as recited in claim 20, including a mid-turbine frame disposed between the fan drive turbine and the two stage turbine section for guiding core flow into the fan drive turbine, the mid-turbine frame supporting a bearing system for one of the fan drive turbine and the two stage turbine section.

22. A turbofan engine as recited in claim 21, including an eight stage second compression section including a last rotating compressor blade with a trailing edge tip that includes a radial length that is greater than 57% of a radial length of the first rotating compressor blade at the leading edge of the eight stage second compression section.

23. The turbofan engine as recited in claim 22, wherein the mid-turbine frame includes a vane guiding a core flow into the fan drive turbine section.

24. The turbofan engine as recited in claim 23, wherein the first compression section includes an efficiency of at least 0.84 and the second compression section includes an efficiency of at least 0.82.

25. The turbofan engine as recited in claim 24, wherein the speed change system comprises an epicyclic gear system that operates at an efficiency of at least 0.985.

26. The turbofan engine as recited in claim 25, wherein the fan includes less than 26 fan blades.

27. The turbofan engine as recited in claim 26, wherein a ratio between the number of the plurality of fan blades and the number of the plurality of stages of the fan drive turbine is between 3.3 and 8.6.

28. The turbofan engine as recited in claim 20, wherein the two stage turbine operates at an efficiency of at least 0.85.
Description


BACKGROUND

A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section. The compressor section typically includes low and high pressure compressors, and the turbine section includes low and high pressure turbines.

The high pressure turbine drives the high pressure compressor through an outer shaft to form a high spool, and the low pressure turbine drives the low pressure compressor through an inner shaft to form a low spool. The fan section may also be driven by the low inner shaft. A direct drive gas turbine engine includes a fan section driven by the low spool such that the low pressure compressor, low pressure turbine and fan section rotate at a common speed in a common direction.

A speed reduction device such as an epicyclical gear assembly may be utilized to drive the fan section such that the fan section may rotate at a speed different than the turbine section so as to increase the overall propulsive efficiency of the engine by allowing an increase in the fan diameter and a reduction in a fan pressure rise. In such engine architectures, a shaft driven by one of the turbine sections provides an input to the epicyclical gear assembly that drives the fan section at a reduced speed such that both the turbine section and the fan section can rotate at closer to their individual optimal speeds.

Although geared architectures have improved propulsive efficiency, turbine engine manufacturers continue to seek further improvements to engine performance including improvements to thermal, transfer and propulsive efficiencies.

SUMMARY

A turbofan engine according to an exemplary embodiment of this disclosure, among other possible things includes a fan section including a fan blade having a leading edge and hub to tip ratio of less than about 0.34 and greater than about 0.020 measured at the leading edge and a speed change mechanism with gear ratio greater than about 2.6 to 1. A first compression section includes a last blade trailing edge radial tip length that is greater than about 67% of the radial tip length of a leading edge of a first stage of the first compression section. A second compression section includes a last blade trailing edge radial tip length that is greater than about 57% of a radial tip length of a leading edge of a first stage of the first compression section.

In a further embodiment of the foregoing turbofan engine, the fan section provides a low fan pressure ratio less than about 1.6.

In a further embodiment of any of the foregoing turbofan engines, the fan section provides a low fan pressure ratio between about 1.45 and about 1.20.

In a further embodiment of any of the foregoing turbofan engines, the fan section provides a bypass ratio greater than about 8.

In a further embodiment of any of the foregoing turbofan engines, the fan section provides a bypass ratio greater than about 8.

In a further embodiment of any of the foregoing turbofan engines, the fan section provides a bypass ratio greater than about 12.

In a further embodiment of any of the foregoing turbofan engines, includes a turbine section that has a fan drive turbine and at least two turbine stages forward of a first turbine blade of the fan drive turbine.

In a further embodiment of any of the foregoing turbofan engines, the fan drive turbine includes at least three stages.

In a further embodiment of any of the foregoing turbofan engines, the fan drive turbine is coupled to the drive the first compression section.

In a further embodiment of any of the foregoing turbofan engines, at least one of the at least two turbine stages is coupled to drive the second compression section.

In a further embodiment of any of the foregoing turbofan engines, the at least two stages include a single turbine second forward of the fan drive turbine.

In a further embodiment of any of the foregoing turbofan engines, the first compression section includes three stages and the second compression section includes eight stages.

A turbofan engine according to an exemplary embodiment of this disclosure, among other possible things includes a fan section providing a bypass ratio greater than about 12, and a speed change mechanism with gear ratio greater than about 2.6 to 1. A first compression section includes a last blade trailing edge tip length that is greater than 67% of the radial length of a first stage leading edge of the first compression section. A second compression section includes a last blade with a trailing edge tip that includes a radial length that is greater than 57% of a radial length of the first stage leading edge of the first compression section.

In a further embodiment of any of the foregoing turbofan engines, the fan section includes a plurality of fan blades supported on a hub. A leading edge of at least one of the fan blades includes a leading edge and a hub to tip ratio is less than about 0.34 and greater than about 0.020 measured at the leading edge.

In a further embodiment of any of the foregoing turbofan engines, includes a turbine section that has a fan drive turbine and at least two turbine stages forward of a first turbine blade of the fan drive turbine.

In a further embodiment of any of the foregoing turbofan engines, at least one of the at least two turbine stages is coupled to drive the second compression section.

In a further embodiment of any of the foregoing turbofan engines, the at least two stages include a single turbine section forward of the fan drive turbine.

In a further embodiment of any of the foregoing turbofan engines, the fan section provides a fan pressure ratio between about 1.45 and about 1.20.

In a further embodiment of any of the foregoing turbofan engines, the first compression section includes three stages and the second compression section includes eight stages.

Although the different examples have the specific components shown in the illustrations, embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples.

These and other features disclosed herein can be best understood from the following specification and drawings, the following of which is a brief description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an example turbine engine according to an embodiment.

FIG. 2 is a schematic view of a compressor section of the example turbine engine according to an embodiment.

FIG. 3 is a schematic view of another compressor section of the example turbine engine according to an embodiment.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates an example gas turbine engine 20 that includes a fan section 22, a compressor section 24, a combustor section 26 and a turbine section 28. Alternative engines might include an augmenter section (not shown) among other systems or features. The fan section 22 drives air along a bypass flow path B while the compressor section 24 draws air in along a core flow path C where air is compressed and communicated to a combustor section 26. In the combustor section 26, air is mixed with fuel and ignited to generate a high pressure exhaust gas stream that expands through the turbine section 28 where energy is extracted and utilized to drive the fan section 22 and the compressor section 24.

Although the disclosed non-limiting embodiment depicts a turbofan gas turbine engine, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines; for example a turbine engine including a three-spool architecture in which three spools concentrically rotate about a common axis and where a low spool enables a low pressure turbine to drive a fan via a gearbox, an intermediate spool that enables an intermediate pressure turbine to drive a first compressor of the compressor section, and a high spool that enables a high pressure turbine to drive a high pressure compressor of the compressor section.

The example engine 20 generally includes a low speed spool 30 and a high speed spool 32 mounted for rotation about an engine central longitudinal axis A relative to an engine static structure 36 via several bearing systems 38. It should be understood that various bearing systems 38 at various locations may alternatively or additionally be provided.

The low speed spool 30 generally includes an inner shaft 40 that connects the fan section 22 and a low pressure (or first) compressor section 44 to a low pressure (or first) turbine section 46. The inner shaft 40 drives the fan section 22 through a speed change device, such as a geared architecture 48, to drive the fan section 22 at a lower speed than the low speed spool 30. The high-speed spool 32 includes an outer shaft 50 that interconnects a high pressure (or second) compressor section 52 and a high pressure (or second) turbine section 54. The inner shaft 40 and the outer shaft 50 are concentric and rotate via the bearing systems 38 about the engine central longitudinal axis A.

A combustor 56 is arranged between the high pressure compressor 52 and the high pressure turbine 54. In one example, the high pressure turbine 54 includes at least two stages to provide a double stage high pressure turbine 54. As used herein, a "high pressure" compressor or turbine experiences a higher pressure than a corresponding "low pressure" compressor or turbine.

The example low pressure turbine 46 has a pressure ratio that is greater than about 5. The pressure ratio of the example low pressure turbine 46 is measured prior to an inlet of the low pressure turbine 46 as related to the pressure measured at the outlet of the low pressure turbine 46 prior to an exhaust nozzle. The low pressure turbine 46 is coupled to the fan section 22 through the geared architecture 48 and therefore is also referred to interchangeably in this disclosure as the fan drive turbine 46.

A mid-turbine frame 58 of the engine static structure 36 is arranged generally between the high pressure turbine 54 and the low pressure turbine 46. The mid-turbine frame 58 further supports bearing systems 38 in the turbine section 28 as well as setting airflow entering the fan drive turbine 46.

Airflow through the core airflow path C is compressed by the low pressure compressor 44 then by the high pressure compressor 52 mixed with fuel and ignited in the combustor 56 to produce high speed exhaust gases that are then expanded through the high pressure turbine 54 and fan drive turbine 46. The mid-turbine frame 58 includes vanes 60, which are in the core airflow path and function as an inlet guide vane for the low pressure turbine 46. Utilizing the vane 60 of the mid-turbine frame 58 as the inlet guide vane for low pressure turbine 46 decreases the length of the low pressure turbine 46 without increasing the axial length of the mid-turbine frame 58. Choosing a high gearbox input to output ratio, reduces the number of vane rows in the fan drive turbine 46 and shortens the axial length of the turbine section 28. Thus, the compactness of the gas turbine engine 20 is increased and a higher power density may be achieved.

The disclosed gas turbine engine 20 in one example is a high-bypass geared aircraft engine. In a further example, the gas turbine engine 20 includes a bypass ratio greater than about eight (8), with an example embodiment being greater than about twelve (12). The geared architecture 48 is an epicyclical gear train, such as a planetary gear system, star gear system or other known gear system, with a gear reduction ratio of greater than about 2.6.

In one disclosed embodiment, the gas turbine engine 20 includes a bypass ratio greater than about twelve (12:1) and a diameter of the fan blades 42 is significantly larger than an outer diameter of the low pressure compressor 44. It should be understood, however, that the above parameters are only exemplary of one embodiment of a gas turbine engine including a geared architecture and that the present disclosure is applicable to other gas turbine engines.

A significant amount of thrust is provided by flow through the bypass flow path B due to the high bypass ratio. The fan section 22 of the engine 20 is designed for a particular flight condition--typically cruise at about 0.8 Mach and about 35,000 feet. The flight condition of 0.8 Mach and 35,000 ft., with the engine at its best fuel consumption--also known as "bucket cruise Thrust Specific Fuel Consumption (`TSFC`)"--is the industry standard parameter of pound-mass (lbm) of fuel per hour being burned divided by pound-force (lbf) of thrust the engine produces at that minimum point.

"Low fan pressure ratio" is the pressure ratio across the fan blade alone, without a Fan Exit Guide Vane ("FEGV") system. The low fan pressure ratio as disclosed herein according to one non-limiting embodiment is less than about 1.50. In another non-limiting embodiment, the low fan pressure ratio is between 1.45 and 1.20.

"Low corrected fan tip speed" is the actual fan tip speed in ft/sec divided by an industry standard temperature correction of [(Tram .degree. R)/(518.7.degree. R)]).sup.0.5. The "Low corrected fan tip speed", as disclosed herein according to one non-limiting embodiment, is less than about 1150 ft/second.

The example gas turbine engine includes the fan section 22 that comprises in one non-limiting embodiment less than about 26 fan blades 42. In another non-limiting embodiment, the fan section 22 includes less than about 20 fan blades 42. Moreover, in one disclosed embodiment the low pressure turbine 46 includes no more than about 6 turbine rotor stages schematically indicated at 34. In another non-limiting example embodiment, the low pressure turbine 46 includes about 3 turbine rotor states. A ratio between the number of fan blades 42 and the number of low pressure turbine rotors is between about 3.3 and about 8.6. The example low pressure turbine 46 provides the driving power to rotate the fan section 22 and therefore the relationship between the number of turbine rotor stages 34 in the low pressure turbine 46 and the number of blades 42 in the fan section 22 disclose an example gas turbine engine 20 with increased power transfer efficiency.

An example disclosed engine 20 provides a system-level combination of component (module) efficiencies and a system-level combination of features within these modules that are used to arrive at uniquely high engine efficiency (i.e. Thrust Specific Fuel Consumption) at takeoff and at bucket cruise. The disclosed combination of components provide benefit in a commercial engine with very high bypass ratio in achieving the stated, very low, thrust specific fuel consumption (see table 1) and is especially beneficial to a single aisle aircraft where the overall pressure ratio of the compressor is less than 50.

TABLE-US-00001 TABLE 1 Sea level takeoff, [2]Sea level takeoff, 86 deg F., 0.0 Mn: 86 deg F., 0.0 Mn: Bucket Test Stand Opera- Test Stand Opera- Cruise, tion: no power tion: no power 0.8 Mn, extraction, no extraction, no 35,000 ft, Environmental Con- Environmental Con- Standard trol System bleed trol System bleed Day Thrust Specific 0.2751 0.53717 Fuel Consump- tion [1] Speed change At least 2.6 2.6 (Input/output) Component efficiency Fan OD at least 0.90 0.9344 0.96501 Speed Change at least 0.985 0.9949 0.99374 Mechanism First Compressor at least 0.84 0.8695 0.86622 or LPC Second Compres- at least 0.82 0.8495 0.8356 sor or HPC Turbine Sec- at least 0.85 for the 0.87544 0.8938 tion(s) ex- single HPT or luding the fan combined efficiency drive turbine if two or more turbines are used Fan Drive turbine at least 0.89 0.9251 0.9266

The combination of module efficiency includes among other possible things, the fan section 22 with the fan blades 42 supported on a fan hub 64. Each of the fan blades 42 includes a leading edge 62 that extends a radial distance 66 from the engine axis A. The fan hub 64 extends a radial distance 68 from the engine axis A. A low hub-tip ratio of fan hub radial radius 68 to the radius at the leading edge 62 of the fan blade 42 is less than 0.34 and greater than 0.020. The disclosed range of ratios is desirable in that the lower this value is, the smaller the outer fan section and inlet section has to be to accommodate a given amount of air, and maintaining this dimension within the desired ratio range enables a reduction in engine weight relative to an engine with a higher hub to tip ratio. In one example embodiment, the fan section 22 further provides a low fan pressure ratio that is between about 1.45 and about 1.20, and a bypass ratio greater than about 8.0.

The disclosed engine 20 includes the geared architecture 48 with a gear ratio greater than about 2.6 to 1. In this example, the speed change system is the geared architecture, which is an epicyclical gearbox and which includes planet gears or star gears interspersed by baffles for gathering and directing lubricant during operation.

The example turbine section 28 has at least two turbine stages forward of the first turbine stage 94 included in the fan drive turbine 46. In this example, the high pressure or second turbine includes two turbine stages 96 forward of the fan drive turbine 46. In this example, the two turbine stages 96 are part of a single high pressure turbine 54 with at least two turbine rotors 96, however, it is within the contemplation of this disclosure that the at least two turbine rotors forward of the fan drive turbine 46 could be part of multiple turbines that rotate independent of each other, for example, two separate turbine sections with at least one turbine rotor each.

Referring to FIG. 2, with continued reference to FIG. 1, the first compression section 44, which in one disclosed example is a low pressure compressor (LPC) 44, includes three stages. The example LPC 44 includes first compressor blade 70 with a leading edge 72 and a last compressor blade 74 with trailing edge 76. A tip of the leading edge 72 of the first blade 70 extends a radial distance 78 from the engine axis A. A tip of the trailing edge 76 of the last blade 74 extends a radial distance 80 from the engine axis A. The first compression section 44 is configured such that a ratio between the radial distance 80 at the trailing edge 76 is greater than 67% of the radial distance 78 of the leading edge 72 of the first blade 70. The example configuration provided by the disclosed ratio enables improved airflow through the first compressor section 44 that provides improved efficiency. The disclosed relationship between the leading edge 72 and the trailing edge 76 enables a beneficial modest slope to the engine casing structures spanning the compressor section 24. The modes slope provides for minimal effects to tip clearances of the compressor blades due to axial shifting of the compressor rotor due to overall aerodynamic loading.

Referring to FIG. 3 with continued reference to FIG. 1, the second compression section 52, which in one disclosed example is a high pressure compressor (HPC), includes at least eight stages. The example HPC 52 includes a first blade 82 with a leading edge 84 that extends a radial distance 86 from the engine axis A to a tip. The second compressor section 52 also includes a last blade 88 having a trailing edge 90 that extends a radial distance 92 from the engine axis A to the tip. A ratio between the leading edge 84 and the trailing edge 90 defines the configuration of the compressor 52 that provides the improved efficiency. In one disclosed example, the radial distance 92 of the trailing edge 90 of the last blade 88 is greater than about 57% of the radial distance 86 of the leading edge 84 of the first blade 82 of the second compressor section 52.

A geared turbofan arrangement for short range aircraft can uniquely exploit the particular aspects of an aircraft duty cycle that is characterized by an unusually low proportion of time in cruise operation versus the total time spent at takeoff and climb power (for a representative time span such as between engine overhauls).

A definition of a short range aircraft is one with a total flight length less than about 300 nautical miles.

TABLE-US-00002 TABLE 2 Engine #1 #2 Max takeoff weight 53,060 kg (117,000 lb) 58,967 kg (130,000 lb) Max landing weight 49,895 kg (110,000 lb) 55,111 kg (121,500 lb) Maximum cargo 3,629 kg (8,000 lb) 4,853 kg (10,700 lb) payload Maximum payload 13,676 kg (30,150 lb) 16,284 kg (35,900 lb) (total) Max range 2,778 km (1,500 nmi) 2,778 km (1,500 nmi) Take off run at 1,219 m (3,999 ft) 1,524 m (5,000 ft) MTOW Landing field 1,341 m (4,400 ft) 1,448 m (4,751 ft) length at MLW

As is shown in Table 2, a short range aircraft for purposes of this disclosure is defined as including a single aisle configuration with 2, 3 seating or 3, 3 seating. Conventionally, a short range aircraft have a capacity of about 200 passengers or less. Moreover, an example short range aircraft will have a maximum range of only about 1500 nautical miles.

Because of the extremely high utilization in terms of cumulative hours at relatively high power during take-off conditions, the disclosed geared turbofan engine 20 arrangement is configured differently to achieve a beneficial balance of fuel burn and maintenance costs. The high power utilization is a result of frequent operation at high power conditions that generate high turbine temperatures, elevated turbine cooling air temperatures and elevated temperatures at the rear stage of the compressor. The result of such operation is that LPC pressures rise, temperature rise and efficiency may be lower than for a long range aircraft. In a long range aircraft that operates for longer periods and a greater portion of the cumulative operating hours, maximizing LPC efficiency is desired provides a significant benefit, and is a key difference when compared to short range aircraft. Pressure and temperature rise can be increased due to the less frequent use of takeoff power between overhaul periods which could be around 4000 hours for both the short range and long range commercial airliner.

Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. For that reason, the following claims should be studied to determine the scope and content of this disclosure.

* * * * *
[Image]
[View Shopping Cart] [Add to Shopping Cart]
[HIT_LIST] [NEXT_LIST] [PREV_DOC] [NEXT_DOC] [Top]
[Home] [Boolean Search] [Manual Search] [Number Search] [Help]