Experimental study on evolution characteristics of plane subsonic-supersonic shear layer

摘要

The study of plane subsonic-supersonic shear layer formed by the subsonic ramjet air and the supersonic rocket jet in the rocket based combined cycle is of profound significance for analyzing the mixing characteristics in combustor. In this study, the mixing features including vortex structures, growth rate and evolution characteristics of pressure unmatched subsonic-supersonic shear layer were experimentally investigated using the ice-cluster based planar laser scattering technique and the subsonic-supersonic shear layer test device. The convective Mach number ranges from 0.38 to 0.73, and the corresponding pressure deviation between both flows is 0 to 32.4%, respectively. Results show that the experimental and theoretical normalized growth rates agree well with each other for the pressure matched case. The pressure mismatch effect could make the shear layer transition in advance and the shear layer deflects to the lower pressure side. And that the deflection angle and the deviation of normalized growth rate are positively correlated with the pressure deviation. Therefore, the pressure mismatch effect could suppress the growth of shear layer even though amending the convective Mach number using the parameters after the expansion wave induced by the pressure mismatch. (C) 2020 Elsevier Masson SAS. All rights reserved.