Aerospace Science and Technology | 2021
Numerical study on the induced-ramp mixed and combustion characteristics of rocket-based combined cycle engine
Abstract
Abstract In the study, the supersonic flow mechanism and mixed characteristics are discussed by changing the ramp angle and momentum flux ratio of the rocket-based combined cycle engines. The three-dimensional Reynolds-averaged Navier-Stokes equations, the shear stress transport k-ω turbulence model, and the Eddy-dissipation concept model are adopted to analyze the flow field structure. The results reveal that the oblique shock wave causes the rocket gas and parallel shear layer to slope downward, thus promoting more efficient combustion. The oblique shock wave interacts with the bottom wall boundary layer and forms a low-velocity region. The increase of the ramp angle is beneficial for jet to enter the combustion chamber. The ramp angle increases from 20° to 40°, and the combustion efficiency increases by about 49%. Furthermore, the increase of the momentum flux ratio is conducive to induce vortex structure, and the best penetration depth of jet fuel is obtained when the momentum flux ratio is 0.72.