隔板截面造型对超声速膨胀器流场及性能的影响

采用三维雷诺平均N-S方程和标准k-ε湍流模型,在设计工况下对3种隔板截面形状的超声速膨胀器的三维流道流场进行了数值研究.结果表明:矩形截面形状的超声速膨胀器近吸力面区域气流速度大,斜激波之后流动损失低,等熵绝热效率较高;正梯形截面形状的超声速膨胀器出口平均绝对马赫数、静压比以及膨胀比大,综合性能相对最优;角区附面层分离、回流形成的低速气流团以及斜激波所导致高速气流的增压过程是出口流动损失的主要来源;优化隔板沿径向的结构,超声速膨胀器的综合性能有望进一步提高. 

Influence on flow field and performance of supersonicexpander with different strake wall section shapes

The three dimensional Reynolds-averaged N-S equations and the standard k-ε turbulent model were adopted to simulate numerically the flow field of the three-dimensional flow-path of the supersonic expander under three kinds of strake wall section shapes at the design point. It's found that the suction surface of supersonic expander with rectangle strake wall section shape has high air velocity, low flow losses after the shock waves, and thus higher adiabatic isentropic efficiency can be obtained; the supersonic expander with positive trapezoid strake wall section shape has high outlet averaged Mach number, static pressure ratio and expansion ratio, its comprehensive performance is relatively optimal; the main sources of flow losses at outlet include low-speed air caused by corner boundary layer separation and backflow as well as pressurization process of high-speed air after oblique shock waves. The comprehensive performance of supersonic expander could be further enhanced by optimizing the structure of strake wall in radial direction.