Influence of injection angle on the mixing efficiency in supersonic flow with a transverse sonic jet

In order to develop an injection method for effective air-fuel mixing and little total pressure loss in scramjet combustion, the influence of injection angle in supersonic flow with a sonic jet is numerically studied. At first, 2-D numerical simulation of a supersonic fiow field with a vertical sonic jet of helium is performed using AUSMDV scheme and κ-ω SST turbulence model with Wilcox compressibility correction, and good agreements between numerical results and experimental data validate the reliability of the numerical method. Whereafter, flowfields with a sonic jet of hydrogen are simulated in five injection angles: 30°, 60°, 90°, 120° and 150°. Two parameters, averaged total pressure and mixing rate, are defined to evaluate the performance of different injection angles. It is found that injection angle of 30° and 60° induce little loss of total pressure but much smaller air-fuel mixing rates. Comparing with injection angle of 90° and 150°, the injection angle of 120° induces a much larger air-fuel mixing rate, while only a bit larger loss of total pressure. Therefore, it is concluded that injection angle of 120° is the optimum choice for fuel injection.