Numerical investigation on shock train characteristics in cylindrical isolator via SATES method

In scramjet，the isolator plays a crucial role as a transitional component between the combustor and the inlet. Within the isolator，complex flow phenomena such as shock wave/boundary layer interactions，flow separation，and shock trains are observed under the influence of high back-pressure from the combustor. In this study，the self-adaptive turbulence eddy simulation（SATES）is used to numerically study the shock train characteristics in a cylindrical isolator. The primary focus is to analyze the potential challenges faced when the isolator is coupled with the combustor，including the effects of constant or pulsating back-pressure at the isolator exit and wall temperature on the shock train characteristics within the isolator. The results indicate that an increase in the exit back-pressure of the isolator，a decrease in the frequency of pulsating back-pressure，and an elevation in wall temperature can all cause the shock train to move towards the inlet，leading to potential unstart risks. Therefore，in practical engineering applications，particular attention should be paid to the high back-pressure and low-frequency oscillations induced during the combustor combustion process，as well as the wall heat conduction effects，to prevent the shock train from being expelled from the isolator，which could result in the unstart of not only the isolator but also the entire engine.