低压涡轮叶栅流动中转捩模型的校验及改进

为评估并提高现有转捩模型的预测精度,采用计算流体力学(CFD)软件FLUENT 12.1,选取层流模型、全湍流模型、剪切应力输运(SST)低雷诺数模型、k-kl-ω模型以及γ-Reθ模型对低压涡轮叶栅T106-EIZ进行数值模拟,通过与实验数据的对比校验了后3种模型对于转捩以及相关参数的模拟能力,并对结果以及模型的作用机理进行分析,校验结果表明所有模型都不能准确地预测分离流转捩以及尾迹诱导转捩.选取预测效果较好的γ-Reθ模型进行了修正,提出通过修改间歇因子输运方程中的参数Ca1和Ca2的方法来修正该模型,结果表明该方法可以提高模拟精度.

Transition Model Assessment and Modification in Low-pressure Turbine Cascade

In order to assess and improve the prediction accuracy of existing transition models, numerical investigations on low-pressure turbine cascade T106-EIZ are conducted with five models: laminar, turbulence, shear stress transport (SST) low Reynolds model, k-kl-ω model and γ-Re_θ model, by using computational fluid dynamics (CFD) software FULENT 12.1. The laminar and turbulence models are used as the baseline models for testing the last three transition models. Their ability to accurately simulate transition and related parameters is also evaluated by comparison with the experimental results. Subsequently, the comparison results and mechanisms of models are analyzed. The results show that no model can accurately predict separated flow transition and wake-induced transition, while the γ-Re_θ model is slightly better than the others. A new method of modifying the γ-Re_θ model is proposed by correcting the constant c_a1 and c_a2 in the transport equation of intermittency factor, and the results show that this method is quite effective in improving prediction accuracy.