横管降膜蒸发器用布液器的数值模拟研究

Numerical Simulation of Liquid Distributor for Falling Film Evaporator in Horizontal Tube

布液器是横管降膜式蒸发器中最重要的设备之一,对流入换热器中的制冷剂进行均匀分配。通过仿真软件FLUENT对某款降膜式蒸发器中的布液器第一层均液结构进行数值模拟,分析了底角、小孔距侧边距离和入口直径变化对布液器布液均匀性的影响。通过分析,发现在布液器入口处存在严重的流量突减,改变底角可以有效改善这种状况;此外,采用较小的侧边距离,布液器的布液均匀性也会得到提升;增大入口直径,入口处的流量突减现象也可以得到有效改善;同时大的底角、较小的小孔距侧边距离和大直径的进液口在提升均液性的同时也可以获得较小的压降。

The liquid distributor is one of the most important equipment in the falling film evaporator of the horizontal tube, which evenly distributes the refrigerant flowing into the heat exchanger. By the simulation software FLUENT, the liquid distributor in a falling film evaporator was numerically simulated, and analyzed the influence of the bottom angle. By analysis, it was found that there was the sudden decrease of mass flow at the inlet of the liquid distributor, but changing the bottom angle could effectively improve this situation. In addition, using small distance between the small hole and the side, the uniformity of liquid distribution would also be improved;increasing the diameter of the inlet can also effectively reduce the sudden decrease of the flow rate at the inlet. At the same time, a large bottom angle, a small distance between the small hole and the side and a large diameter inlet can improve liquid distribution and also obtain a small pressure drop.