三维磁流体强化超燃冲压发动机数值模拟

Simulation of three-dimensional magnetohydrodynamic enhanced scramjet

建立了三维磁流体强化超燃冲压发动机内部黏性流场的求解模型.针对马赫数为6设计了联合应用磁控进气道和磁流体能量旁路的磁流体强化超燃冲压发动机模型.针对该模型进行了数值模拟研究,分析其中的三维流场结构、电参数分布规律以及能量转换特性.结果表明:当飞行马赫数为8时,磁控进气道的应用能够使头部压缩激波回到唇口,使分离区消失,内进气道中的流动恢复到设计状态.磁流体能量旁路可有效降低燃烧室入口处的马赫数,从而改善发动机性能.其中发生器中的流动参数和电参数的分布比较理想,效果显著;而加速器要取得显著的加速效果则需要大量的能量输入.在加速器中,电极附近焦耳耗散严重,导致局部高温以及流动的复杂性,性能不够理想.

Simulation model of the three-dimensional magnetohydrodynamic（MHD） enhanced scramjet viscous inner flow field was established.Geometry of a scramjet applied both MHD controlled inlet and MHD energy bypass was designed at Ma=6.Numerical simulation was performed,and three-dimensional flow field structure,distribution pattern of the electric parameters,and characteristics of energy transformation were analyzed.The results show when flight Ma=8,MHD controlled inlet can be used to draw the compressive shock waves back to the cowl lip,the separation zone disappears,and the flow field of the inner inlet recovers to the design condition.The MHD energy bypass can decrease Ma of the flow before combustor efficiently,so as to improve engine performance.In the MHD generator,distributions of flow and electric parameters are comparatively ideal to make efficient effect,while the MHD accelerator needs large amount of energy input to make a significant acceleration.In the MHD accelerator,Joule heating dissipation is severe near the electrodes,which results in local high temperature,flow field complication and performance deterioration of the MHD accelerator.