基于DDES的跨声速导叶中激波与边界层干涉机理研究

Study of Shock Wave-Boundary Layer Interaction Mechanism in a Transonic Vane Based on DDES

关键词:  透平导叶  混合方法  激波  边界层分离

Key words:  Turbine guide vanes  Hybrid method  Shock wave  Boundary layer separation

摘要:

随着透平负荷的逐渐提高，为了分析导叶中出现的激波与边界层干涉的流动机理，需要使用高精度、高分辨率的求解器和先进的湍流计算方法以获取精细的流场结构。采用自主开发的混合RANS/LES求解器，对高负荷透平环境中激波与边界层干涉的流动现象进行研究。结果表明:跨声速流场中同时存在强激波和弱激波，弱激波可在作用位置附近导致熵生成率增大；强激波会诱导边界层分离，而分离区的存在使激波出现马赫反射现象。进一步对湍动能和流动损失进行了机理研究，发现在分离泡前湍动能较大，且湍动能的生成和对流占主导机制；在强激波后由强激波引起的熵生成率较大，且强激波前后区域流动损失主导因素不同。

Abstract:

With the gradual increase in turbine load， to analyze flow mechanism of interaction between shock waves and boundary layer appearing in the nozzle guide vanes， it is necessary to get access to high-accuracy， high-resolution solver and advanced turbulent calculation method for the fine flow field structure. A self-developed hybrid RANS/LES flow solver was used to study flow phenomena of the interference process between shock wave and boundary layer in the high load turbine flow field. The results show that， there are weak shocks and strong shock in the transonic flow field， and the weak shocks can result in large entropy generation rate in the position of them. Strong shock wave can induce boundary-layer separation， and the separation zone makes the shock appear Mach reflection phenomenon. In the further mechanism study of turbulent kinetic energy and flow loss， turbulent kinetic energy is large before the separation bulb， and it is mainly dominated by convective term and production term. The entropy generation rate is large after the position of strong shock wave owing to the existence of strong shock wave， and the dominant factors of flow loss before and after strong shock wave are different.