双室蒸发分离室内流动及蒸发过程的数值模拟

Numerical simulation of flow and evaporation process in dual-chamber evaporation separation chamber

掌握双室双管程蒸发器分离室内汽液二相流动及蒸发过程特性是其进一步结构优化的基础,应用STARCCM+软件对分离室内隔离板上平衡孔的形状和位置对汽液二相流动及蒸发过程的影响进行了数值模拟。模拟结果表明:分离室内隔离板上平衡孔较佳的形状为圆形孔,其适宜的设置位置为距分离室底部与距汽液入口处距离之比在2∶3—2∶1之间。设置在该区域时,分离室内流场均匀,流动阻力损失较小,推动力较大;在平衡孔形状及位置较佳的情况下,分离室一内液位高于分离室二,隔离板两侧温度分布相对比较均匀,并能够建立起稳定的温度差和浓度差,在分离室上方汽液能够实现较好的分离;模拟结果进一步证实了双室双管程蒸发器实际操作的可行性。

Mastering the characteristics of vapor-liquid two-phase flow and evaporation process in double separation chambers and double tube passes was the base for further structure optimization separation chamber. The effects of the shape and position of the balance hole in separation chamber of evaporator on vapor-liquid two-phase flow and evaporation process were numerical simulated by STAR-CCM ＋ software. The simulation results show that the better shape of balance hole on isolation plate is round,and it is appropriately located at which the distance ratio of the bottom of the separation chamber and the vapor-liquid entrance is between 2∶ 3 to 2∶ 1. In this region,the flow field of separation chamber is uniform,flow resistance loss is smaller and impetus is larger. In such good circumstances,liquid level of separation chamberⅠis higher than that of separation chamber Ⅱ,the temperature distribution on the both sides of isolation plate is relatively uniform,and the stable temperature differences and concentration differences can be set up,the vapor-liquid at the top of separation chamber is separated properly,which is further confirmed the feasibility of the actual operation of evaporator with double separation chambers and double tube passes.