A LOOSE COUPLING NUMERICAL SIMULATION METHOD BETWEEN FLOW FIELD AND ELECTROMAGNETIC FIELD OF HYPERSONIC VEHICLE

Among the many solutions to the communication blackout problem of hypersonic re-entry vehicles, the electromagnetic control method is one of the most feasible methods. A precise electromagnetic control scheme not only needs to accurately consider the effect of the applied electromagnetic field on the conductive fluid, but also needs to consider the effect of the induced electromagnetic field caused by the high-speed motion of the fluid on the conductive fluid. For the typical flight state of a hypersonic vehicle, the full MHD method is difficult to be directly used in the simulation of the coupling between flow field and electromagnetic field due to the problem of numerical rigidity, and the low magnetic Reynolds number approximation method cannot consider the effect of the induced magnetic field on the conductive fluid. Aiming at the difficulties and deficiencies in the application of the two classic methods of MHD to the design of electromagnetic control methods for hypersonic vehicles, this paper numerically solves the flow governing equation NS equation and the electromagnetic governing equation hyperbolic Maxwell equation, and combines them together by a loosely coupled iterative solution, and finally, a numerical simulation method suitable for coupling between flow field and electromagnetic field of hypersonic vehicle is established. The numerical method is verified by two test cases, and that is MHD shock reflection and two-dimensional supersonic MHD nozzle. Based on the numerical method in this paper, the coupling problem between flow field and electromagnetic field in a typical flight state of a hypersonic vehicle under the action of an applied dipole magnetic field is studied. The numerical simulation results show that, at the state of the magnetic Reynolds number 0.7557, when the effect of induced magnetic field on the fluid is ignored, the shock stand-off distance is 11.11% larger than that when the induced magnetic field is considered. The error cannot be ignored. For the flight state, the interaction between the flow field and the magnetic field should be fully considered instead of only considering the influence of the applied magnetic field on the flow field motion.