基于熵产理论的高负荷离心叶轮流动损失分析研究

Flow Losses Analysis of Highly-Loaded Centrifugal Impeller Based on Entropy Generation Theory

高负荷离心叶轮被广泛应用于小型航空发动机中,了解其内部流动损失特性对进一步提升离心压气机性能有着至关重要的作用。本文采用熵产理论,对高负荷离心叶轮内的损失来源和分布特性进行分析。研究结果表明,湍流黏性耗散引起的熵产是总熵产的主要组成部分,叶顶泄漏、流动分离为叶轮内流动损失的主要来源。随着质量流量和转速的增加,流动分离逐渐加剧,总熵产增大,但各熵产来源的占比基本保持不变。当质量流量增加时,叶顶泄漏流强度增大,分流叶片吸力面上的流动分离位置逐渐向叶顶方向迁移。当转速增加时,叶顶泄漏流影响范围扩大,分流叶片上的分离位置向上游叶根迁移。

Highly-loaded centrifugal impellers are widely applied in small aviation engines.It's crucial to understand the internal fow loss characteristics in an impeller to improve the performance of a centrifugal compressor.In the paper,the entropy generation theory was adopted to analyze the loss source and distribution in a highly-loaded centrifugal impeller.The results indicate that,the entropy generation caused by the turbulent viscous dissipation is the main component of total entropy generation.The blade tip leakage and flow separation are the main sources of fow loss in the impeller.As the mass fow rate and rotational speed increase,the flow separation gradually intensifies and the total entropy production increases,but the proportions of entropy production from each source basically remain the same.When the mass flow rate increases,the intensity of tip leakage flow increases.And the separated fow on the suction surface of the splitter blade approaches towards the blade tip direction.As the speed increases,the infuence scope of tip leakage flow expands.The separation position on the splitter blade migrates towards the blade root upstream.