Numerical Investigation of Back Pressure and Free-stream Effects on a Mixed Compression Inlet Performance

Document Type : Article


Department of Aerospace Engineering, Sharif University of Technology, Tehran, Iran


Inlet Performance has an important role in the operation of air-breathing propulsion systems. In this study, performance of a supersonic axisymmetric mixed-compression inlet in the supercritical operating condition is numerically studied. The effects of free-stream Mach number and engine-face pressure on performance parameters, including mass flow ratio, drag coefficient, total pressure recovery, and flow distortion are investigated. To this sake, a multi-block density-based finite volume CFD code is developed and Reynolds-averaged Navier-Stokes equations with Spalart-Allmaras one-equation turbulence model is employed. The code is validated by comparing numerical results against other computational results and experimental data for two test cases of inviscid flow in a two-dimensional mixed-compression inlet and flow in an external compression inlet. Finally, the code is utilized for investigation of a specific supersonic mixed-compression inlet with the design Mach number of 2.0 and length to diameter ratio of 3.4. Results revealed that the increment of free-stream Mach number leads to decrease in total pressure recovery and drag coefficient, while mass flow ratio and flow distortion increase. The effects of engine-face pressure on performance parameters showed that by increasing the engine-face pressure, mass flow ratio and drag coefficient remain constant while total pressure recovery increases and flow distortion decreases.


Main Subjects


1. Mattingly, J.D., Heiser, W.H., and Pratt, D.T., Aircraft
Engine Design, New York: American Institute of
Aeronautics and Astronautics (2002).
2. Xie, L. and Guo, R. Investigation of a twodimensional
mixed-compression hypersonic inlet",
Hangkong Xuebao/Acta Aeronautica et Astronautica
Sinica, 30(12), pp. 2288-2294 (2009).
3. Apyan, A.C., Orkwis, P.D., Turner, M.G., Duncan, S.,
Benek, J., and Tinnaple, J. Mixed compression inlet
simulations with aspiration", in 50th AIAA Aerospace
Sciences Meeting Including the New Horizons Forum
and Aerospace Exposition, Nashville, TN (2012).
4. Vaynshtein, A. and Arieli, R. Start/Un-start process
for a sudden opening of a mixed compression inlet
system of a ramjet engine", in 54th Israel Annual
Conference on Aerospace Sciences, IACAS 2014, Tel-
Aviv and Haifa, pp. 899-920 (2014).
5. Yongzhao, L., Qiushi, L., and Shaobin, L. Modeling
the e ect of stability bleed on back-pressure in mixedcompression
supersonic inlets", Journal of Fluids Engineering,
Transactions of the ASME, 137(12), 121101
6. Qiushi, L., Yongzhao, L., and Shaobin, L. A quasi
one-dimensional bleed
ow rate model for terminal
760 A. Ebrahimi and M. Zare Chavoshi/Scientia Iranica, Transactions B: Mechanical Engineering 25 (2018) 751{761
normal shock stability in mixed compression supersonic
inlet", Proceedings of the Institution of Mechanical
Engineers, Part C: Journal of Mechanical
Engineering Science, 228(14), pp. 2569-2583 (2014).
7. Chyu, W.J., Kawamura, T., and Bencze, D.P. Calculation
of external-internal
ow elds for mixedcompression
inlets", Computer Methods in Applied
Mechanics and Engineering, 64(1-3), pp. 21-37 (1987).
8. Chan, J.-J. and Liang, S.-M. Numerical investigation
of supersonic mixed-compression inlet using an implicit
upwind scheme", Journal of Propulsion and Power,
8(1), pp. 158-167 (1992).
9. Akira, F. and Nobuo, N. Experimental and numerical
investigation of Mach 2.5 supersonic mixed compression
inlet", in 31st Aerospace Sciences Meeting, Reno,
NV, U.S.A. (1993).
10. Mizukami, M. and Saunders, J. Parametrics on 2D
Navier-Stokes analysis of a Mach 2.68 bifurcated rectangular
mixed-compression inlet", 31st Joint Propulsion
Conference and Exhibit, American Institute of
Aeronautics and Astronautics (1995).
11. Jain, M.K. and Mittal, S. Euler
ow in a supersonic
mixed-compression inlet", International Journal for
Numerical Methods in Fluids, 50(12), pp. 1405-1423
12. Akbarzadeh, M. and Kermani, M. Numerical simulations
of inviscid air
ows in ramjet inlets", Transactions
of the Canadian Society for Mechanical Engineering,
33(2), pp. 271-296 (2009).
13. Kwak, E. Lee, H., and Lee, S. Numerical simulation
ows around axisymmetric inlet with bleed regions",
Journal of Mechanical Science and Technology, 24(12),
pp. 2487-2495 (2011).
14. Kotteda, V.M.K. and Mittal, S. Viscous
ow in a
mixed compression intake", International Journal for
Numerical Methods in Fluids, 67(11), pp. 1393-1417
15. Zhao, H., Xie, L.R., Guo, R.W., Tneg, Y.L., and
Zhang, J. Study of start/unstart phenomenon of
supersonic inlet in acceleration/deceleration process",
Hangkong Dongli Xuebao/Journal of Aerospace Power,
30(8), pp. 1841-1852 (2015).
16. Kotteda, V.M.K. and Mittal, S. Computation of
ow in a mixed compression intake", International
Journal of Advances in Engineering Sciences
and Applied Mathematics, 6(3), pp. 126-141 (2015).
17. Ebrahimi, A. and Zare Chavoshi, M. E ect of free
stream Mach number on a mixed compression inlet
performance", Modares Mechanical Engineering,
16(7), pp. 275-284, (2016). (in Persian)
18. Suzen, Y.B. Numerical computation of compressible,
turbulent high-Speed
ows", 9900518 Thesis, Wichita
State University, Ann Arbor (1998).
19. Blazek, J. Turbulence modelling", in: Computational
Fluid Dynamics: Principles and Applications, Chapter
7, 2nd Edn., pp. 227-270, Oxford: Elsevier Science
20. Spalart, P.R. and Allmaras, S.R. A one-equation turbulence
model for aerodynamic
ows", 30th Aerospace
Sciences Meeting and Exhibit, Reno, NV, U.S.A.
21. Slater, J.W. Veri cation assessment of
ow boundary
conditions for CFD analysis of supersonic inlet
NASA TM 2012-211790, National Aeronautics and
Space Administration, Glenn Research Center (2002).
22. Kim, H., Kumano, T., Liou, M.S., Povinelli, L.A.,
and Conners, T.R. Flow simulation of supersonic inlet
with bypass annular duct", Journal of Propulsion and
Power, 27(1), pp. 29-39 (2011).
23. Kwak, E. and Lee, S. Numerical study of the e ect
of exit con gurations on supersonic inlet buzz", 31st
AIAA Applied Aerodynamics Conference, San Diego,
CA (2013).
24. Allmaras, S.R. and Johnson, F.T. Modi cations and
clari cations for the implementation of the Spalart-
Allmaras turbulence model", In Seventh International
Conference on Computational Fluid Dynamics (ICCFD7),
Big Island, Havaii, pp. 1-11 (2012).
25. Roe, P.L. Approximate Riemann solvers, parameter
vectors, and di erence schemes", Journal of Computational
Physics, 43(2), pp. 357-372 (1981).
26. Van Leer, B. Towards the ultimate conservative
di erence scheme", Journal of Computational Physics,
135(2), pp. 229-248 (1997).
27. Anderson, W.E. and Wong, N.D. Experimental investigation
of a large scale, two-dimensional, mixedcompression
inlet system-performance at design conditions,
M = 3.0", NASA TM X-2016 (1970).
28. Soltani, M.R. and Farahani, M. E ects of angle
of attack on inlet buzz", Journal of Propulsion and
Power, 28(4), pp. 747-757 (2011).
29. Soltani, M.R., Farahani, M., and Sepahi Younsi,
J. Performance study of a supersonic inlet in the
presence of a heat source", Scientia Iranica, 18(3), pp.
375-382 (2011).
30. Soltani, M., Sepahi Younsi, J., and Daliri, A. Performance
investigation of a supersonic air intake in the
presence of the boundary layer suction", Proceedings
of the Institution of Mechanical Engineers, Part G:
Journal of Aerospace Engineering (2014).
31. Soltani, M.R., Younsi, J.S., Farahani, M., and Masoud,
A. Numerical simulation and parametric study of a
A. Ebrahimi and M. Zare Chavoshi/Scientia Iranica, Transactions B: Mechanical Engineering 25 (2018) 751{761 761
supersonic intake", Proceedings of the Institution of
Mechanical Engineers, Part G: Journal of Aerospace
Engineering, 227(3), pp. 467-479 (2012).