Experimental study on shock wave control in high-enthalpy hypersonic flow by using SparkJet actuator

SparkJet (SPJ) actuator was used to control shock and shock-on-shock interaction in high-enthalpy hypersonic flow with a total temperature of 4490 K and Mach number 6.9 for the first time. Aiming at the characteristics of rarefied gas in hypersonic flight environment, the control authority of SPJ actuator was improved by air supply method. The process of SPJ interacting with high-enthalpy hypersonic crossflow near a ramp was obtained by using high-speed schlieren camera. When pressurized cavity pressure was 133 kPa, ramp distance was 22 mm and ramp angle was 50, SPJ can eliminate 68.3 % of the whole ramp shock. Results of different experiment cases showed that, within a certain range, the control effect of SPJ on ramp shock improves with the increase of pressurized cavity pressure, ramp distance and the decrease of ramp angle. The elimination of shock by SPJ can be explained by the upward motion of the sonic line in the boundary layer due to the formation of SPJ shock, the thickening of boundary layer and the heating of local flow field. Except for the elimination of shock, the shock intersection point moves upstream and downstream corresponding to the strength changes of SPJ and SPJ shock. Accordingly, local high heat flow around the shock intersection point can be decreased. The control effect of SPJ on shock-on-shock interaction can be improved by properly increasing discharge energy.