考虑旋转和曲率的湍流模型修正及应用
Modification for Turbulence Model Considering Rotation and Curvature with Applications

通过分析湍流模型在模拟旋转和弯曲壁面的旋转机械内流时存在的问题发现,在原有湍流模型的基础上考虑旋转和曲率效应是提高离心泵内流模拟精度和改善流动不稳定性的必然选择;在k？拨？ SST模型中通过考虑旋转和曲率修正,同时引入Hellsten的理查德森数修正模型思想和扩展内秉旋转张量修正,生成了一种新的湍流模型;应用改进后的湍流模型对比转数为34？？34的离心泵在不同工况下的内流场进行了数值模拟,并将改进前后的数值计算结果与试验结果进行了详细对比,由此分析了泵内部流场的分布规律。研究结果表明:改进后的湍流模型预测的能量性能与试验值更接近;在0.6倍设计流量工况下,改进后湍流模型的扬程预测精度提高了3％,效率预测精度提高了近2％,这一结论在内流场中得到了验证;与原湍流模型相比,改进后湍流模型明显改善了叶轮流道和蜗壳扩散段处的流动情况。该结果可为湍流模型研究提供参考。
Analyzing the problems in the numerical simulation for inner flow by original turbulence model in rotary machines, it is found necessary to totally consider the effects of rotation and curvature for enhancing the numerical accuracy and improving instability of centrifugal pump inner flow. The effects of rotation and curvature in k？拨？ SST model are taken into account, and a modified turbulence model based on Richardson number from Hellsten is Built. Then the improved turbulence model is adopted to simulate the steady？？state inner flow in a centrifugal pump at specific speed of 34？？34 under different operating conditions. A comparison between the experimental data and numerical results from the original and modified models reveals the law of pump inner flow. The hydraulic performance predicted by the improved model gets closer to the experimental results than that by original one. In the case of the flow rate of 0.6Qd, the head accuracy and the precision of efficiency predicted by the improved turbulence model increase by 3％ and 2％, respectively. The inner flow of pump under 0.6Qd verifies the superiority of the improved turbulence model, and the turbulent flows both in impeller passages and diffusor are improved obviously