Numerical Study on the Effect of Pulsed Jet on Scramjet Combustion Performance

To decrease the mass flowrate of air throttling into the scramjet combustor, the pulsed jet was used to enhance the combustion characteristics of the scramjet engine. The present study utilized unsteady numerical simulations to investigate the effects on the combustion performance of an ethylene scramjet combustor of non-jet, steady jet and the pulsed jet. The influences of the pulsed jet on the combustion performance were discussed under various duty ratios and waveform conditions. The results demonstrate that the steady jet enhances the mixing efficiency of ethylene and air by generating shock train, which makes the combustion more sufficient. The pulsed jet can further enhance the improvement of air throttling on combustion. The duty ratio and waveform of the pulsed jet mainly affect the flow field structure and combustion performance by changing the intensity of the jet. With the decrease of the duty ratio of the pulsed jet, the wall pressure intensifies, and the combustion efficiency enhances, leading to a significant increase in thrust.