Effect of Ramp Height on Fuel-Air Mixing Characteristics for Dual Transverse Injection behind the Ramp in Supersonic Air Crossflow

To improve the mixing of fuel and air in supersonic flows, various methods are used, including the implementation of a ramp ahead of the injection port. In the present work, the effect of ramp height on the area of double hydrogen jet cross-jet flow in supersonic airflow has been investigated numerically and the effect of ramp height on parameters such as mixing efficiency, effective mixing area ratio and stagnation pressure losses has been investigated. Numerical simulations have been performed using the solution of the three-dimensional Reynolds-Averaged Navier-Stokes equations with the two-equation sst k-ω turbulent model. Initially, the results of the numerical solution are validated with the experimental data. It was shown that the numerical solution results have good agreement with experimental data. Then, the effect of the presence of a ramp upstream of the injection port is numerically investigated for several ramps with different heights. The results show that by increasing the height of the ramp from zero to 6 mm, the mixing efficiency at the exit plane increases from 0.37 to 0.52 and the effective mixing area ratio at the exit plane increases from 0.059 to 0.1. Stagnation pressure losses also increase from 8% to 9%.