超音速风洞扩压器激波串现象的数值模拟

超音速扩压器性能研究具有非常重要的工程实际应用价值。该文为加深对超音速风洞扩压器内流场结构的理解,采用Fluent软件对“收缩段等直段扩张段”型扩压器流场进行了数值计算,较好模拟了扩压器中由激波/边界层干扰诱导的复杂流场的流场特性,再现了流场中的“激波串”和“伪激波”现象,与文献结果吻合较好。并以比较精细的二维网格计算结果对激波串的形成机理和典型流动结构进行了分析,同时应用于实际工程,对某超音速风洞扩压器不同二喉道长度状态下的扩压效率进行了比较。

Numerical simulations of the shock train in the diffuser of a supersonic wind tunnel

The diffuser is one of the key devices in a supersonic wind tunnel. The flow field in the diffuser is very complicated and is characterized by strong shock/boundary layer interaction. The phenomenon is called "shock train". In this paper, the flows in diffusers with varying cross sectional areas were simulated using Fluent. The numerical results illustrate the shock/boundary layer interaction and the shock train phenomenon. The formation of the shock train was analyzed. Two main mechanisms affecting the formation of the shock train, namely the shock induced by adverse pressure gradient and the self-stabilizing effects of the flows were identified. The flow structures of the shock train were studied in detail and the flow stabilizing effects of the diffusers were explained in terms of these structures. The influences of the length of the secondary throat on the pressure recovery efficiency were discussed.