Estimation of inlet airflow non-uniformity effect on turbofan thrust

Аuthors

Ezrokhi Y. A.^*, Khoreva E. A.^**

Central Institute of Aviation Motors named after P.I. Baranov, CIAM, 2, Aviamotornaya str., Moscow, 111116, Russia

*e-mail: yaezrokhi@ciam.ru
**e-mail: 30105@ciam.ru

Abstract

The article considers methodical approaches to developing mathematical model using “parallel compressors” method, intended for estimation of inlet flow non-uniformity effect on aircraft engine basic parameters. On the example of a two-shaft turbo-jet engine calculation at two characteristic cruise modes the results of calculated estimation, where the base value of σ_st and averaged value of σ_av stayed invariable, were presented. Parametric calculations herewith were performed for each selected relative value of the reduced pressure area.

It was demonstrated that degree of full pressure inlet non-uniformity effect on the engine thrust at the two considered modes differs significantly. Thus, if at subsonic mode this estimation could be reduced to accounting only for the effect of reduction of the averaged value of the total pressure at the inlet, while at supersonic cruise mode such reduction use might lead to considerable errors. With invariable values of pressure recovery factor at the engine entry, corresponding to the flight speed for the typical air intake, external compression σ_st and averaged value σ_av, the flow non uniformity factor Δσ_nu affects mainly the thrust. The degree of this parameter effect herewith depends significantly on the difference of s_st and s_av.

The obtained results of calculated estimations of temperature field non-uniformity at the engine inlet effect revealed that the dependence of relative thrust reduction only at the cost of relative heating was similar for the two considered modes (transonic maneuvering and supersonic flight). At the transonic mode herewith, corresponding to higher values of the reduced rotation frequency of both compressor stages, the thrust decay occurs less intensely due to relatively smaller decrease of air flow rate through the engine with reduced rotation frequency decrease due to air temperature rise at the inlet. As for the difference between the values of total thrust decay , which does characterize the effect of the input temperature field non-uniformity, with the increase of relative heating at the transonic mode it rises more intensively. It is explained by the fact that at this mode due to the less difference between air consumptions in air-gas channels of «parallel compressors» (more «dence» location of pressure downstream brunches) the speeds difference and, consequently, static pressures between the flows is much greater, than at the supersonic flight mode, which stipulates the higher losses level while these flows interaction.

Keywords:

total pressure and temperature non-uniformity at the engine inlet, circumferencial non-uniformity, radial non-uniformity, parallel compressors method, turbofan thrust reduction

References

1. Trifonov A.K., Kolesinskii P.D., Zlobin V.I. Aviatsionnaya promyshlennost', 2012, no. 2, pp. 6-10.

2. Longley J.P., Greitzer E.M. Inlet Distortion Effects in Aircraft Propulsion System Integration. NASA Technical Reports Server. 1992. Conference Paper 92-AD-20694, 18 р.

3. Ezrokhi Yu.A., Kalenskii S.M., Morzeeva T.A., Khoreva E.A. Vestnik Moskovskogo aviatsionnogo instituta, 2018, vol. 25, no. 1, pp. 57-66.

4. Nechaev Yu.N., Fedorov R.M., Kotovskii V.N., Polev A.S. Teoriya aviatsionnykh dvigatelei, Moscow, VVIA im. prof. N.E. Zhukovskogo, 2005/2006, 366+448 p.

5. Krasnov S.E., Vorob'eva N.G. Tekhnika vozdushnogo flota, 2012, no. 4, pp. 32-44.

6. Arkhipov D.V., Tumashev R.Z. Vestnik dvigatelestroeniya, 2013, no. 2, pp. 130-135.

7. Greitzer E.M. Surge and rotating stall in axial flow compressors. Part I “Theoretical Compression System Model”. Journal of Engineering for Power, 1976, vol. 98, no. 2, pp. 190-198. DOI: 10.1115/1.3446138

8. Greitzer E.M. Surge and rotating stall in axial flow compressors. Part II “Experimental Results and Comparison with Theory”. Journal of Engineering for Power, 1976, vol. 98, no. 2, pp. 199-211. DOI: 10.1115/1.3446139

9. Krasnov D.S., Semernyak L.I. Tekhnika vozdushnogo flota, 1999, no. 1, pp. 36-54.

10. Kurzke J. Effects of Inlet Flow Distortion on the Performance of Aircraft Gas Turbines. ASME Turbo Expo 2006: Power for Land, Sea, and Air (May 811 2006, Barcelona, Spain). 2006, vol. 2, pp. 117-125. DOI: 10.1115/GT2006-90419

11. Shul'gin A.F., Pavlov Yu.I., Taran E.M. Aviatsionnaya promyshlennost', 2012, no. 2, pp. 24-28.

12. Ye Wei, Qiao Weiyang & Hou Mingjie. Study for the Effect of Combined Pressure and Temperature Distortion on a Turbojet Engine. Modern Applied Science, 2011, vol. 5, no. 3, pp. 123-129. DOI: 10.5539/mas.v5n3p123

13. Krasnov S.E. Tekhnika vozdushnogo flota, 2016, vol. 90, no. 2-3, 86 p.

14. Khoreva E.A., Ezrokhi Yu.A. Aerokosmicheskii nauchnyi zhurnal, 2017, vol. 3, no. 1, available at: http:// aerospace.elpub.ru/jour/article/view/59 DOI: 10.24108/rdopt.0117.0000059

15. Demenchenok V.P., Druzhinin L.N., Parkhomov A.L., Sosunov V.A., Tskhovrebov M.M., Shlyakhtenko S.M., Elperina A.S. Teoriya dvukhkonturnykh turboreaktivnykh dvigatelei (Turbojets theoty), Moscow, Mashinostroenie, 1979, 432 p.

16. Goryunov A.I., Goryunov I.M. Vestnik UGATU, 2010, vol. 14, no. 3(38), pp. 57-61.

17. Davis, Milt W. and Cousins, William T. Evaluating Complex Inlet Distortion with a Parallel Compressor Model. Part 2 “Applications to Complex Patterns”. ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition (June 6–10, 2011, Vancouver, British Columbia, Canada). 2011, vol. 1, pp. 13-23. DOI: 10.1115/GT2011-45068

18. Mazzawy R.S. Multiple Segment Parallel Compressor Model for Circumferential Flow Distortion. Journal of Engineering for Power, 1977, vol. 99, no. 2, pp. 288-296. DOI: 10.1115/1.3446288

19. Ezrokhi Yu.A., Khoreva E.A. Aerokosmicheskii nauchnyi zhurnal, 2017, vol. 3, no. 3, available at: http://aerospace.elpub.ru/jour/article/view/64 DOI: 10.24108/aersp.0317.0000064

20. Cousins W.T., Davis M.W. Evaluating complex inlet distortion with a parallel compressor model. Part 1 “Concepts, theory, extensions and limitations”. ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition (June 610, 2011, Vancouver, British Columbia, Canada). 2011, vol. 1, 12 р. DOI: 10.1115/GT2011-45067