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Scramjet Diagnostics

a scramjet flying
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Supersonic combustion ramjets, or scramjets, are air-breathing engines designed for high-speed flight in the atmosphere.

Scramjets maintain supersonic flow throughout the engine and use a series of oblique shocks to increase the pressure at the combustor inlet. Scramjets are theoretically an optimal propulsion method for air-breathing hypersonic flight vehicles due to their relatively small energy losses, and because they require none of the complex moving parts characteristic of other supersonic propulsion systems. However, there are several significant unsolved engineering challenges associated with controlling supersonic combustion in scramjet combustors.

In the Hanson Research Group, we develop and deploy state-of-the-art laser diagnostics to characterize the supersonic flow field and gas dynamics within scramjet engines [1–2]. We also leverage our expertise to predict and thereby suppress combustion instabilities in these systems, including monitoring for engine unstart [3].

a chart conveying gas temperature, pressure, and wall temperature over time
Time-history of temperature and pressure in a scramjet combustor before, during, and after an unstart event, as measured by optical diagnostics using wavelength modulation spectroscopy (WMS) [3].

To learn more, check out some of our publications:

 [1] I.A. Schultz, C.S. Goldenstein, C.L. Strand, J.B. Jeffries, R.K. Hanson, C.P. Goyne, “Hypersonic Scramjet Testing via Diode Laser Absorption in a Reflected Shock Tunnel,” J. Propulsion and Power, Vol 30 (2014) pp. 1586–1594. DOI: 10.2514/1.B35220

[2] M. Gamba, V.A. Miller, M.G. Mungal, R.K. Hanson, “Combustion Characteristics of an Inlet/Supersonic Combustor Model,” AIAA Aerosp. Sci. Meet. Inc. New Horizons Forum Aerosp. Expo. (2012). DOI: 10.2514/6.2012-612

[3] G.B. Rieker, J.B. Jeffries, R.K. Hanson, T. Mathur, M.R. Gruber, C.D. Carter, “Diode laser-based detection of combustor instabilities with application to a scramjet engine,” Proc. Comb. Inst., Vol 32 (2009) pp. 831–838. DOI: 10.1016/j.proci.2008.06.114