Investigation on the Applicable Scope of Geometrical Throat in RBCC Variable Structure Combustion Chamber

The geometrical throat of variable structure combustion chamber can improve the performance of ramjet engine. For purpose of expand the range of application of geometrical throat of variable structure RBCC engine and study the performance in high flight Mach number, stream thrust analysis method was firstly adopted. It shown that combustor geometrical throat can be utilized up to flight Mach number Ma=7.0 with the limiting temperature of 3 000 K. Based on the configuration of Ma=6.0 variable combustion chamber, three-dimensional numerical simulation of the engine flow path at Ma=6.0, 6.5 and 7.0 was carried out to comparative analyze the flow field details. The results show:the geometrical throat has a positive effect of the heat release to combustion of RBCC under conditions of high flight Mach number, and has a better engine performance, validated the geometrical throat can be applied to the Mach number Ma≤7.0. Finally, the results of ground direct-connect experiment in the simulated flight Mach number Ma=6.0 condition show that the geometrical throat can ensure the efficient and stable combustion of the combustion chamber.