Study on combustion characteristics of sinusoidal hydrogen pulsed jet with different frequencies in supersonic flows

Pulsed jets can effectively improve mixing and combustion efficiencies, while sinusoidal pulsed jets have the advantages of good performance and simple setup. Therefore, the three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations and Shear Stress Transfer k-omega model (SST) are utilized to study the combustion characteristics of sinusoidal pulsed jets with three different frequencies and steady jet in order to obtain an approach to improve the combustion performance in the supersonic flow. In the current study, the combustion performances of the steady jet and the pulsed jets with an equal average momentum flux ratio to the steady jet are compared and analyzed, and the instantaneous combustion characteristics of four different time points in one cycle of the pulsed jets are analyzed in detail. The obtained results show that the pulsed jet can obviously improve the combustion efficiency, although the total pressure loss is slightly larger than that of the steady jet. On the whole, the pulsed jets have a good impact on the combustion performance of the combustor, and the combustion performance of the f = 20 kHz pulsed jet case is the best in this study.