Reynolds-average Navier-Stokes study of steady and pulsed gaseous jets with different periods for the shock-induced combustion ramjet engine

Abstract

The mixing process is very important for the shock-induced combustion ramjet engine. In the current study, the steady jet, as well as pulsed jets with different periods, is investigated in order to achieve adequate fuel/air mixing in the supersonic flow. Flow field properties are studied numerically based on grid independency analysis and code validation. The influence of the hydrogen distribution, as well as the flow field parameters such as mixing efficiency, total pressure recovery coefficient, and fuel penetration depth, is deeply analyzed for different jet-to-crossflow pressure ratios, namely, 10.29 and 25.15. The obtained results predicted by the three-dimensional Reynolds-averaged Navier-Stokes equations coupled with the two equation shear stress transport k-ω turbulence model show that the grid scale makes only a slight difference to wall pressure profiles. The pulsed jets with different periods are beneficial for the mixing process, especially when the jet-to-crossflow pressure ratio is high, and it has special advantages on reducing the total pressure loss and improving the fuel penetration depth. Among the pulsed jets considered in the current study, the T1 pulsed jet with higher frequency has the best performance, and its mixing augmentation mechanism is predicted. Its mixing enhancement mechanism is focusing on merging a mass of air around into the fuel core by the intermittent injection.