Numerical investigations on the improvement of burning conditions in the scramjet

Paper number

IAC-18,C4,9,12,x47319

Author

Prof. Sterian Danaila, Romania, University POLITEHNICA of Bucharest - Research Center for Aeronautics and Space

Coauthor

Dr. Dragos Isvoranu, Romania, University POLITEHNICA of Bucharest - Research Center for Aeronautics and Space

Coauthor

Dr. Alina Bogoi, Romania, University POLITEHNICA of Bucharest - Research Center for Aeronautics and Space

Coauthor

Dr. Constantin Leventiu, Romania, University POLITEHNICA of Bucharest - Research Center for Aeronautics and Space

Year

2018

Abstract

Different to the ramjet solution, the scramjet alternative is confronted with the flame auto-ignition and stability problems during the supersonic combustion. If in the ramjet case, the intake device ensures a configuration of the reflected shock waves such that the terminal shock wave is normal and the flow in the combustion chamber is subsonic, in the scramjet case, the normal shock wave is transformed in an oblique one and the flow stays supersonic downstream the intake device. However, in order to ensure optimal burning conditions, Mach number should remain as low as possible, while the static pressure and temperature have to be kept at their highest values. Not only the extreme values are important but also the uniformity of the distribution of velocity, pressure and temperature fields.
The present paper goal is to investigate the possibilities of increasing the efficiency of the intake device (scramjet solution) by controlling the separation zones due to shock waves boundary layer interactions and by reconfiguration of the hole structure of the shock waves system to obtain optimal burning conditions in the combustion chamber.
The most important tools of such an endeavor are the distribution of temperature on the walls of the intake/scramjet, injection/suction of air, wall porosity as well as their combinations.
The results show that, for example, heating a portion of the intake wall over the adiabatic temperature of the flow leads to a 40% increase of the static pressure at the inlet in the combustion chamber and to a significant more uniform pressure distribution. Also, the solution chosen for air injection is able the control of the separation zone and to reconfiguration of the shock waves system with the same benefic outcomes with respect to static pressure increase at the outlet from the intake device.
The outcomes of this research may lead to the preliminary design of a state-of-the-art intake device for flows with Mach numbers up to 5 with and without incidence.

Abstract document

IAC-18,C4,9,12,x47319.brief.pdf

Manuscript document

IAC-18,C4,9,12,x47319.pdf (🔒 authorized access only).

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