关键词: 航空航天推进系统, 化学非平衡, 数值模拟, 磁场, 高超声速, 激波脱体距离, 电导率

Abstract: Three dimensional hypersonic viscous chemical nonequilibrium flows around a blunt body under the effect of a dipole magnetic field are numerically investigated. The electrical conductivity is calculated by a species formula, with the chemical kinetics described by 7 species and 6 reactions between them. The magnetic field and the flow field are coupled by the magnetic induction equation. The finite volume method is implemented in the spatial discretization. Central difference approximation is applied to the diffusion terms while a second order upwind scheme is used for the convection terms, and a 3-stage Runge-Kutta scheme is adopted for the time integration. The results show that the shock standoff distance, skin friction coefficient and surface heat flux all increase with the strengthening of the external dipole magnetic field. When external magnetic field is 0.153T, the shock standoff distance, local skin friction coefficient and local surface heat flux in the frozen flow increase respectively by three times, 63% and 61%, while in the chemical nonequilibrium flow, the shock standoff distance, local skin friction coefficient and local surface heat flux increase by 50%, 47% and 31%, respectively, as compared with the figures without the effect of the magnetic field. Meanwhile, the maximal temperature of the shock layer in the chemical nonequilibrium flow is 64% of that in the frozen flow when external magnetic field is 0.153T.

Key words: aerospace propulsion system, chemical nonequilibrium, numerical simulation, magnetic fields, hypersonic, shock standoff distance, electrical conductivity