基于非线性耦合本构关系的高速磁流体控制数值模拟

Numerical simulation of hypersonic magnetofluid control based on non-linear coupling constitutive relation

  • 摘要: 针对高速等离子体在磁场中的复杂非线性流动问题,由于连续介质理论的N-S方程已不再适用,本文通过耦合非线性耦合本构方程和Maxwell电磁场控制方程,结合Park TTv双温度模型和Park11组分化学反应模型,建立了低磁雷诺数高速磁流体热化学非平衡数值模拟方法。基于高速等离子体圆柱扰流算例的数值模拟,研究了偶极子磁场对高速磁流体控制的影响机理,重点分析了磁场的存在以及磁感应强度的大小对等离子体流场结构的影响。研究结果表明:磁场将会显著影响高速等离子体流场结构,磁感应强度增大,带电粒子所受洛伦兹力增强,导致弓形激波脱体距离增大,当B0 = 3T时,激波脱体距离增幅达452.38%;驻点热流变化受磁感应强度、来流高度、来流马赫数共同影响,当H = 80 km时,加入磁场后热流降幅达45.55%;此外,磁场对高速磁流体热化学非平衡效应影响较为显著,主要体现在波后N2的离解程度和近壁面的复合反应等方面,而对O2的离解过程影响不大。

     

    Abstract: To address the complex nonlinear flow mechanisms of high-speed plasma in magnetic fields, the conventional‌ Navier-Stokes (N-S) equations based on continuum theory fail to provide accurate predictions. Therefore, A novel framework was developed by‌ coupling the Nonlinear Coupling Constitutive Relations (NCCR) with Maxwell's electromagnetic field governing equations, augmented with the Park's TTv two-temperature model and the Park 11-component chemical reaction model. This integration established‌ a numerical simulation method and code for hypersonic magnetohydrodynamic (MHD) thermochemical non-equilibrium under‌ low magnetic Reynolds numbers conditions‌. Numerical simulations of high-speed plasma flow past a spherical body were conducted to investigate the influence mechanism of a dipole magnetic field on high-speed MHD control, with particular focus on‌ the effects of magnetic field existence‌ and its induction strength on plasma flow field structures. The results show that the presence of a magnetic field significantly alters high-speed plasma flow structures, with stronger magnetic fields inducing greater Lorentz forces on charged particles and consequently increasing bow shock detachment distances (e.g., a 452.38% increment observed at B0 = 3 T). Stagnation point heat flux variations exhibit dependence on multiple factors including magnetic induction strength, inflow altitude, and Mach number, showing a notable 45.55% reduction at H = 80 km after magnetic field introduction. Furthermore, the magnetic field induces prominent thermochemical non-equilibrium effects, primarily enhancing N2 dissociation in post-shock regions while modifying recombination reactions near walls, yet exerting minimal influence on O2 dissociation dynamics.

     

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