某超燃冲压发动机尾喷管的三维流场特性

超燃冲压发动机结构简单,推重比大,应用前景广阔.但其流场结构十分复杂,研究超燃冲压发动机三维流场结构具有重要的意义.采用计算流体力学软件对某超燃冲压发动机尾喷管的三维流场进行数值模拟,先后得到了流场的密度、马赫数、涡量及速度矢量线图.结果表明:喷管内及侧壁面出口处存在膨胀波.各个壁面出口处附近的流场存在羽流激波和剪切层,内喷管出口周围的羽流激波和剪切层呈环状分布在流场周围,上壁面尾部受羽流激波的影响产生一道由压强决定的管内斜激波.内喷管出口及上壁面尾部处也均存在流向涡结构.

Three dimensional flow characteristics of a scramjet nozzle

Scramjet has the advantages of simple structure, high thrust to weight ratio and wide application prospect. But its flow field structure is very complex, so it is important to study the three-dimensional flow field structure of scramjet. The three-dimensional flow field of scramjet nozzle was simulated by CFD software. The distribution of density, Mach number, vorticity and velocity vector were obtained. The results show that there are expansion waves in the nozzle and at the exit of the sidewall. There are plume shock wave and shear layer in the flow field near the exit of each wall. The plume shock wave and shear layer around the inner nozzle exit are annular distribution around the flow field. There are oblique shock waves generated by boundary layer separation at the tail of the upper wall. The flow at the exit of the inner nozzle and the tail of the upper wall are affected by the plume at their respective positions, and the flow direction turns inward, resulting in the formation of vortex near the shear layer.