敞口式离心喷嘴内部及近喷口区域的流动特性

为了深入理解敞口式离心喷嘴雾化机制，基于界面追踪法VOF（volume of fluid）和RNG（renormalization group）湍流模型对敞口式离心喷嘴进行数值模拟，计算结果与PDPA（phase Doppler particle analyzer）及单反相机测得的喷嘴出口速度和雾化锥角一致性较高.清晰地捕获了中心空气涡结构及喷嘴内部的回流区，展现了切向孔与旋流室的交互影响，并着重分析了液膜厚度演变特性及喷嘴内外速度场发展规律.随着喷注压降的增加，破碎长度降低，打开长度及喷雾角增加.揭示了敞口式离心喷嘴独特的流动机制，为喷嘴雾化性能预测及结构优化提供依据. 

Flow field in and near the open-end swirl injector

A numerical simulation using the VOF (volume of fluid) interface tracking method and RNG(renormalization group)turbulence model was carried out in order to deeply understand the atomization mechanism of the open-end swirl injector. The feasibility of the numerical calculation was verified by using PDPA(phase Doppler particle analyzer) and camera to measure the injector exit velocity and the spray angle. The central air core and the recirculation regions in the injector were captured. And the interaction between the tangential inlets and swirling chamber was revealed. What''s more, the evolving characteristic of the liquid film thickness and the development law of the internal and external velocity field were emphatically analyzed. With the increasing of the pressure drop, the breaking length decreases while the opening length and the spray angel increase. The unique mechanism of the open-end swirl injector is revealed so it can be helpful to predict of the atomization performance and the structure optimization.