Aerodynamic Characteristics of the Opposing Jet Combined with Magnetohydrodynamic Control in Hypersonic Nonequilibrium Flows

To improve the thermal protection effect of an opposing jet, a novel thermal protection technology (i.e., an opposing jet combined with magnetohydrodynamic (MHD) control technology) is proposed in this study. Considering the flight conditions of an ELECTRE vehicle and the unsteady state of the opposing jet, we employed the time-accurate nonequilibrium N-S equations coupled with a low-magnetic-Reynolds-number model to explore the jet characteristics, thermal protection effects, and aerodynamic drag characteristics of this novel technology. Two jet conditions (PR2.53 and PR5.07) and four magnetic field conditions (no-MHD, B0 = 1 T, 2 T, and 4 T) were employed. The results show that the introduction of a magnetic field can guide the flow of the opposing jet by reconstructing the shock, where the reattachment shock is pushed away from the surface and the shock standoff distance (SSD) increases. Compared with the opposing jet and the MHD control technologies, this novel technology can provide a better thermal protection effect. In particular, it enables a long penetration mode (LPM) jet, which aggravates the aerodynamic heating environment around the vehicle at lower flow rates to provide effective thermal protection for the vehicle. Moreover, this novel technology can achieve effective thermal protection without increasing the aerodynamic drag at an appropriate jet mass flow rate and a magnetic field strength. For example, under the B0 = 2 T magnetic field, the ratios of peak wall heat flux for the two technologies (the MHD control technology and the PR2.53 jet combined MHD control technology) are 0.908 and 0.820, respectively, whereas the ratios of average drags for the two technologies are 1.235 and 0.993, respectively.