微通道分流弹状流的界面过程及压力演变规律

发布时间：2018-07-18 16:43

【摘要】：弹状流分流不仅能调控两相流流型从而强化传热,同时也是生物化工、制药行业的传统过程。针对壁面微通道分流液相、调控两相流型的过程进行数值模拟,获得局部参数变化规律,是获得两相流流型演变机理的基础。采用VOF模型耦合动态自适应网格精准追踪气液界面,模拟气液界面在分液口的界面运动;获得轴向及壁面静压、动压的演变规律。通过模拟可知微通道分流弹状流的关键是气弹在分液口的类活塞运动;同时由于界面拉普拉斯压力差的存在,弹状流压降具有不连续性;且此不连续压力随气弹在分液口的类活塞运动具有周期波动性。而弹状流液桥部分的局部压降是影响总压降的关键;近气弹头部的液相区压降显著,近气弹尾部的液相区域由于液速降低其压降明显衰弱;此为弹状流有别于其他两相流流型的压降特点。
[Abstract]:Slug flow can not only regulate the flow pattern of two-phase flow to enhance heat transfer, but also is a traditional process in biochemical and pharmaceutical industries. Based on the numerical simulation of the process of regulating the two-phase flow pattern in the wall microchannel, the variation of local parameters is obtained, which is the basis of obtaining the evolution mechanism of the two-phase flow pattern. The VOF model coupled with dynamic adaptive mesh is used to accurately track the gas-liquid interface, which simulates the movement of the gas-liquid interface at the nozzle, and obtains the evolution law of axial and wall static pressure and dynamic pressure. The simulation results show that the key to split slug flow in microchannel is the piston movement of the gas slug at the nozzle, and the pressure drop of the slug flow is discontinuous due to the existence of the pressure difference in the interface of Laplacian. The discontinuous pressure fluctuates periodically with the piston motion at the nozzle. The local pressure drop of the slug liquid bridge is the key to affect the total pressure drop, the pressure drop in the liquid region near the head of the gas bomb is significant, and the pressure drop in the liquid region near the end of the gas bomb is obviously weakened because of the decrease of the liquid velocity. This is the pressure drop characteristic of the slug flow which is different from other two-phase flow patterns.
【作者单位】：华北电力大学能源动力与机械工程学院;低品位能源多相流与传热北京市重点实验室;
【基金】：国家自然科学基金项目(51576063) 中央高校优青项目~~
【分类号】：O359.1

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