基于能量梯度理论的回流器入口安装角对离心压缩机性能影响研究

摘要

Steady three-dimensional Navier-Stokes equations and the Spalart-Allmaras turbulent model are used for numerical simulation of centrifugal compressor performance with different return channel stagger angle.The energy gradient theory is applied to analyze the flow field in return channels.The distribution of the energy gradient function K is obtained for each model.The results show that under the design conditions, the stage performance comes to the best when return channel stagger angle equals to 37°.According to the analysis of energy gradient function K in different conditions, it is found that the instability easily happens in the tail and exit position of the return channel blade and the flow field is more stable under the design conditions.Distribution of K values along the axial direction of different models are analyzed and found that K value is the smallest within 37°~46°, and the flow in the return channel is stable.In the same return channel, the flow return channel may easily happen near the hub.%利用定常的三维Navier-Stokes方程和Spalart-Allmaras (S-A)湍流模型,对不同回流器入口安装角的离心压缩机级性能进行了数值模拟;并利用能量梯度理论对不同入口安装角下的回流器内部的流动状况进行分析,得到每一种模型的能量梯度函数K的分布.结果表明:在设计工况下,回流器入口安装角在37°附近时多变效率和压比最高;通过对不同工况下的回流器进行能量梯度函数K值分析,发现回流器内流动最容易失稳的地方主要处于回流器叶片的尾部及出口位置,且相对其他流量工况,设计工况下回流器内的流动最稳定;分析不同入口安装角回流器沿轴向不同截面的K值分布,发现在37°~46°范围内的K值最小,回流器内的流动较为稳定;同一回流器中,越靠近轮盖位置,流动越容易出现不稳定.