Oil separation is commonly needed in air conditioning and refrigeration systems to reduce the oil circulation rate and keep the oil inside the compressor. For compactness, the oil separation structure integrated into the compressor is more and more popular than traditional external oil separators. However, a quantitative guideline for the design of oil separation structure is missing for irregular geometry and realistic flow condition at the compressor discharge. This paper presents impinging separation mechanism, one of the basic mechanisms of droplet separation. The separating structures are studied by flow visualization and experimental measurement under realistic compressor discharge conditions. The video of oil mist flowing through the baffles and plates is captured by a high-speed camera and analyzed quantitatively. The effect of the oil flow condition and the effect of separator geometry design are investigated based on the experimental data. With the help of flow visualization, the flow details are analyzed, and a semi-empirical model is proposed to predict the separation efficiency and pressure drop of a certain wave-plates structure. The results and conclusions from this study give useful guidelines about how to reduce the oil circulation ratio by designing oil separators.

空调和制冷系统中通常需要油分离，以降低油循环速率并将油保留在压缩机内。为了紧凑，集成到压缩机中的油分离结构比传统的外部油分离器越来越受欢迎。但是，对于不规则的几何形状和实际的压缩机出口流量条件，缺少油分离结构设计的定量指南。本文介绍了撞击分离机制，这是液滴分离的基本机制之一。在实际的压缩机排气条件下，通过流动可视化和实验测量研究了分离结构。流过折流板和挡板的油雾视频由高速摄像机捕获并进行定量分析。根据实验数据，研究了油流条件的影响和分离器几何设计的影响。在流动可视化的帮助下，对流动细节进行了分析，并提出了一个半经验模型来预测某一波片结构的分离效率和压降。这项研究的结果和结论为如何设计油分离器降低油循环比提供了有用的指导。