气冷涡轮环形叶栅三维流场的实验与数值研究

EXPERIMENTAL AND NUMERICAL RESEARCH FOR 3-D FLOW FIELD OF ANNULAR TURBINE CASCADE WITH FILM COOLING

采用4种不同的湍流模型对叶片表面带小孔射流的环形涡轮叶栅内部流场进行数值计算,并与热线实验测量结果进行了对比。结果表明,由于射流尾迹的影响,在射流附近靠近壁面处产生二次流,二次流随着射流下游距离的增大逐渐减弱。比较不同湍流模型的计算结果发现,采用κ-ε模型在射流尾迹区域和与主流掺混区域的计算结果与实验吻合较好,B-L模型在近壁面的速度计算结果偏大,其对尾迹区域二次流的捕捉也较差。

Four different turbulence models were applied to simulate three-dimensional flow field in annular turbine cascade with film cooling. Predictions with different turbulence models have been compared with the experimental results to reveal how well the models capture the features of the flow. Results indicate that secondary flow were generated near the holes because of the jet wake and weakened gradually downstream along the hole center. Comparing the computational results of four different turbulence models, κ-ε model provides the best comparison with the experimental data. The computational results of B-L model overpredict the velocities in the near-wall region, and this model is not very well suited for the simulation of the secondary flow in the wake region.