气液同轴双离心式喷嘴喷雾特性

采用流体体积方法分析涡流器离心式喷嘴内部流动过程,采用单反相机和相位多普勒测速仪测量离心式喷嘴、气液同轴双离心式喷嘴的喷雾特性。发现涡流器离心式喷嘴内部流动的总压损失主要发生在涡流器槽道入口、收敛段和等直段。等直段使液膜厚度减小,喷雾锥角减小。离心式喷嘴喷雾粒径分布范围沿径向逐渐增加,轴向速度分布范围沿径向先减小后逐渐增加。气液同轴双离心式喷嘴喷雾特性受气液比影响很大,气液比小时旋流空气使喷雾锥角增加,粒径分布范围减小;气液比大时,气体膨胀压缩喷雾,使大液滴能够到达喷雾中心,喷雾外侧为二次雾化成的细小液滴。

Spray characteristic of gas-liquid double swirl coaxial injector

Interface-tracking method volume of fluid (VOF) was used to simulate the flow process in pressure swirl injector. SLR camera was used to measure the spray cone angle, PDA was used to measure the diameter and axial velocity of pressure swirl and gas-liquid double swirl coaxial injector. The results show that total pressure loss lies mostly in liquid swirler inlet, convergent section, and columned section. The longer the columned section is, the thicker the film and the small the spray cone angle is. The range of diameter distribution increases with radius and that of axial velocity decreases firstly and then increases with radius. Spray characteristic of gas-liquid double swirl coaxial injector is greatly influenced by gas-liquid ratio (GLR). While GLR is small enough, swirling air increase the spray cone angle and decrease the range of diameter distribution. While GLR is large enough, the expansion of air compress the spray, pushing large particle to the center of the spray. And at the edge of spray locate small particles from second atomization.