Numerical Studies on Flow Field Characteristics of Cavity Based Scramjet Combustors

Authors: Rakesh Arasu, Sasitharan Ambicapathy, Sivaraj Ponnusamy, Mohanraj Murugesan, V. R. Sanal Kumar

Abstract:

The flow field within the combustor of scramjet engine is very complex and poses a considerable challenge in the design and development of a supersonic combustor with an optimized geometry. In this paper comprehensive numerical studies on flow field characteristics of different cavity based scramjet combustors with transverse injection of hydrogen have been carried out for both non-reacting and reacting flows. The numerical studies have been carried out using a validated 2D unsteady, density based 1st-order implicit k-omega turbulence model with multi-component finite rate reacting species. The results show a wide variety of flow features resulting from the interactions between the injector flows, shock waves, boundary layers, and cavity flows. We conjectured that an optimized cavity is a good choice to stabilize the flame in the hypersonic flow, and it generates a recirculation zone in the scramjet combustor. We comprehended that the cavity based scramjet combustors having a bearing on the source of disturbance for the transverse jet oscillation, fuel/air mixing enhancement, and flameholding improvement. We concluded that cavity shape with backward facing step and 45o forward ramp is a good choice to get higher temperatures at the exit compared to other four models of scramjet combustors considered in this study.

Keywords: Flame holding, Hypersonic flow, Scramjet combustor, Supersonic combustor.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1086821

References:

[1] J. Tamagno, and O. Lindemann, Experimental Results on Supersonic Combustion, General Applied Science Laboratories, Ronkonkoma, NY, December 1962.
[2] I. T. Osgerby, H. K. Smithson, and D. A. Wagner, “Supersonic combustion tests with a double-oblique-shock SCRAM jet in a shock tunnel”, AIAA J., vol. 8, no. 9, pp. 1703-1705, 1970.
[3] G. Y. Anderson, C. R. McClinton, and J. P. Weidner, “Scramjet performance”, In: Scramjet Propulsion, E. T. Curran and S. N. B.Murthy Eds., Reston, VA: AIAA Progress in Astronautics andAeronautics, 2000, vol. 189, pp. 369-446.
[4] D. C. Hunt, A. Paull, R. R. Boyce, and M. Hagenmaier, “Investigation of an axisymmetric scramjet configuration utilising inletinjection and radical farming”, in proceedings of 19th International Symposium on Airbreathing Engines Montreal, Canada, September 2009.
[5] J. R. McGuire, R. R. Boyce, and N. R. Mudford, “Radical farm ignition processes in two-dimensional supersonic combustion”, J. Propulsion Power, vol. 24, no. 6, pp. 1248-1257, 2008.
[6] M. K. Smart, “Scramjets”, Aeronautical J., vol. 111, no. 1124, pp. 605- 620, 2007.
[7] M. K. Smart, and C. A. Trexler, “Mach 4 Performance of hypersonic inlet with rectangular-to-elliptical shape transition”, J. Propulsion Power, vol. 20, no. 2, pp. 288-293, 2004.
[8] H. Ogawa1, R. R. Boyce1, A. Isaacs and T. Ray, “Multi-Objective Design Optimisation of Inlet and Combustor for Axisymmetric Scramjets, The Open Thermodynamics Journal, 2010, 4, 86-91.
[9] Satish Kumar et al., “Scramjet combustor development,” Internal Report, Hypersonic Propulsion Division, DRDL, India, 2005.
[10] C. McClinton, A. Roudakov, V. Semenov, V. Kopehenov, AIAA Paper 96-4571, 1996.
[11] T. Mathur, M. Gruber, K. Jackson, J. Donbar, W. Donaldson, T. Jackson, F. Billig, J. Prop. Power 17 (6) (2001) 1305–1312.
[12] Jeong-Yeol Choi, Fuhua M, Vigor Yang, “Combustion oscillations in a scramjet engine combustor with transverse fuel injection,” Proceedings of the Combustion Institute 30 (2005) 2851–2858.
[13] J.Y. Choi, I.S. Jeung, Y. Yoon, AIAA J. 38 (7) (2000) 1179–1187.
[14] A. Paull, R. J. Stalker and D. J. Mee, “Experiments on supersonic combustion ramjet propulsion in a shock tunnel”, J. Fluid Mech., vol. 296, pp. 159-183, 1995.
[15] R. J. Stalker, A. Paull, D. J. Mee, R. G. Morgan, and P. A. Jacobs,“Scramjets and shock tunnels – The Queensland experience”, Prog Aerosp Sci., vol. 41, pp. 471-513, 2005.