Secondary fuel jet strategies on mixing enhancement performance of rocket-based combined cycle engine

Abstract

The mixed augmentation performance between secondary fuel jet and uneven supersonic inflow is a significant evaluation index of the rocket-based combined cycle engine. In this study, the effects of the secondary fuel jet on the flow field structure and mixing enhancement performance are discussed by changing both the secondary fuel jet angle and spacing of multiple rows of jet holes. The three-dimensional coupled implicit Reynolds averaged Navier-Stokes equations, SST k-ω turbulence model, and eddy dissipation concept (EDC) reaction model were adopted to evaluate the flow field structure with a sonic hydrogen jet. It is indicated that the 135° fuel jet has the largest penetration depth value, followed by the 90° fuel jet, whereas the 45° fuel jet has the smallest penetration depth value. However, the 45° fuel jet possesses the best mixing performance, it easily induces a pair of downstream counter-rotating vortex, and the oblique torque is further generated to aggravate the tearing ability to the jet. The three jet holes induce a stronger shock wave and form a larger barrier under the 90° jet. Additionally, when the spacing between the multiple rows of jet holes reduces, penetration depth is easily created. Further, when the spacing of the three rows of jet holes is larger, the fluctuation of the mixing coefficient increases.