Numerical analysis of the step jump structure of a scramjet flow by the DSMC method

Computations using the direct simulation Monte Carlo method are presented for hypersonic rarefied flow over a supersonic combustion ramjet (scramjet). The primary object of this study is to examine the geometrical effects of a step jump on flow field structures. The sensitivity of internal flow properties, including shock interaction, vortex, pressure and temperature distributions to free-stream Mach number and configuration variations, such as the step height and the ratio of isolator to combustor, is analyzed. Comparisons are made between cases with various configurations, based on surface pressure and temperature. It is shown that different isolator to combustor ratios and expansion ratios cause profoundly different results. The flow structures generated in the scramjet inlet directly affect vehicles operating at high speeds and high altitudes.