Magnetic field control of high-enthalpy shock wave/boundary-layer interactions using a fully implicit thermochemical non-equilibrium solver

Abstract

Magnetohydrodynamic (MHD) heat shield systems have been proven to be highly effective in hypersonic blunt-nosed bodies. Thus, it is natural to consider the application of MHD to more complex geometries that induce shock wave/boundary-layer interactions associated with locally high heat load, which is a lack of deep research, especially for the large-size model in high-enthalpy conditions. To investigate the possibility and mechanism of the control of shock wave/boundary-layer interactions using local magnetic fields, the partially ionized flow of the hollow cylinder/flare coupling of these fields was numerically analyzed using a hypersonic thermochemical nonequilibrium solver. It consisted of an 11-species reaction model and a Park two-temperature model based on the low magneto-Reynolds assumption. To address the numerical stiffness introduced by the large difference in the characteristic time of the thermochemical non-equilibrium and grid refinement in the boundary layer and interaction zone, a fully implicit block lower–upper symmetric Gauss–Seidel algorithm was developed. This algorithm improved the accelerating rate and the solver was validated using cases involving MHD control of flow around a typical reentry vehicle, and the measured double cone and hollow cylinder/flare data for a high-enthalpy wind tunnel. After that, a parametric study of high-enthalpy flow over the hollow cylinder/flare model was conducted and MHD control was divided into three categories. Among these, N-type control led to the largest reduction in the peak value of the total wall heat flux near the neck region, which was obtained using a uniform magnetic field. Specifically, the peak heat flux and the peak skin friction coefficient were reduced by 20.0% and 48.0%, respectively. Then, two local MHD interaction parameters were newly proposed for mechanism analysis and can serve as an effective indicator for MHD controllability. The numerical results demonstrated that the Lorentz force in the counter-streamlined direction induced by the external magnetic field and ionized flow were key factors that influenced the control of the local heat flux. The results of this study lay the foundation for the design of MHD experiments in a high-enthalpy wind tunnel.