悬臂斜坡喷注器流场结构与混合特性

Flowfield structure and mixing performance of a cantilevered ramp injector

为了探索高马赫数下激波诱燃冲压发动机前体/进气道燃料/空气混合的精细流场结构和混合增强机理,采用隐式方法,对悬臂斜坡喷注器进行了三维RANS仿真,得到了喷注器流场的精细结构。仿真结果表明,由于斜坡的作用,流场中产生了激波、膨胀波、流向旋涡等现象。气流经过斜坡时产生了斜激波,并在斜坡边缘处发生膨胀;斜坡侧壁附近在压差的作用下产生了流向旋涡,流向涡在向下游发展过程中卷吸空气,从而增强了混合,但斜坡的存在加大了流场的总压损失。

In order to investigate the precise flowfield structure and mixing-enhanced mechanism of H2/air mixture for the forebody / inlet of shock-induced combustion ramjet（ shcramjet） at high Mach number,numerical simulations were conducted to study the H2/air mixing enhancement and flowfield of the cantilevered ramp injector. An implicit finite volume method was used to solve the 3D compressible Navier-Stokes equations. Simulation results show that,in general,due to the effect of the ramp,physical phenomenon,like shock,expansion wave,and longitude vortices etc. are produced in the flowfield. Oblique shock occurs when the freestream meets the ramp. And the flow expands at the edge of the ramp. Longitude vortices appear along with pressure difference,which whirl the air in the movement downstream. So in this way the H2 and air mix better,but the ramp increases the total pressure losses.