基于OpenFOAM的离心压气机流场数值研究

Numerical Study on Flow Field of Centrifugal Compressor Based on OpenFOAM

基于开源平台OpenFOAM建立离心压气机数值计算程序,分别使用SSTk-ω和Spalart-Allmaras两种湍流模型对带无叶扩压器的离心压气机进行了全流道数值模拟,从压力、速度、熵产等多个角度分析了离心压气机内部流场特性,探究了不同湍流模型对数值模拟结果的影响。结果表明:SST k-ω能更好地反映二次流、涡流、流动分离等现象,Spalart-Allmaras湍流模型中叶轮射流-尾流影响较大;由间隙泄漏流引起的低速区从叶顶前缘逐步发展到叶顶尾缘,最后进入无叶扩压器进行增压降速,形成了流动损失,降低了离心压气机效率;离心压气机内部高熵区主要集中在轮盖侧,轮盘侧相对于轮盖侧熵值较小,离心压气机流道内部熵值随叶高增加而增加。

A numerical calculation program for centrifugal compressors was established based on the open source platform OpenFOAM. Two turbulence models, SST k-ω and Spalart-Allmaras, were used to simulate the full-flow channel of a centrifugal compressor with a bladeless diffuser. Pressure, entropy and other angles were used to analyze the internal flow field characteristics of the centrifugal compressor, and the effects of different turbulence models on the numerical simulation results were explored. The results show that SST k-ω can better reflect the secondary flow, vortex, flow separation and other phenomena. The impeller jet-wake flow has a greater impact on the Spallart-Allmaras turbulence model;The low-speed zone caused by the gap leakage flow gradually develops from the leading edge of the blade tip to the trailing edge of the blade tip, and finally enters the bladeless diffuser to increase the pressure and reduce the speed, forming a flow loss and reducing the efficiency of the centrifugal compressor;The high entropy area inside the centrifugal compressor is mainly concentrated on the wheel cover side. The entropy value of the wheel disk side is relatively small compared to the wheel cover side. The internal entropy value of the centrifugal compressor runner increases with the increase of the leaf height.