新型旋流布液器成膜性能实验研究

EXPERIMENTAL STUDY ON FILM FORMING PERFORMANCE OF NEW TYPE SWIRLING LIQUID DISTRIBUTO

布液器是降膜蒸发器的关键部件。文章针对现有布液器存在的不足,开发了一种新型旋流布液器。该布液器为切向开槽结构,槽一侧与管内壁相切,另一侧延伸一定长度与管内壁形成导流结构,下端与换热管通过螺纹连接。在有机玻璃实验装置内对新型旋流布液器和切向槽型布液器形成液膜等性能进行了系统的对比研究。实验结果表明:只要合理控制流量,两种布液器均能连续稳定成膜,不会出现“干管”现象;新型旋流布液器的最小成膜流量更小,成膜的流量范围更广,说明其操作弹性更大;在相同流量下,新型旋流布液器比切向槽型布液器形成的液膜厚且流速小,因此液膜稳定性更好,同时液膜在换热管内的停留时间更长,换热效果更好。

Liquid distributor is the key component of falling film evaporator.In view of the shortcomings of the current liquid distributor,a new type swirling liquid distributor was developed.This liquid distributor is tangential slot structure;one side of the slot is tangent to the inner wall;the other side extends a certain length to form a diversion structure with the inner wall and the lower end is connected with the heat exchange tube through threads.The film forming performance of the new type swirling liquid distributor and tangential slot liquid distributor was systematically compared in the plexiglass experimental device.The experimental results show that with reasonable control of flow rate,both kinds of liquid distributor can continuously and stably form film without"dry tube"phenomenon;the minimum wetting rate of the new type swirling liquid distributor is smaller and the film-forming flow range is wider,which indicates that the operation elasticity of the new type liquid distributor is greater;at the same flow rate,the liquid film is thicker and the flow rate is slower in the new type liquid distributor than those of tangential slot liquid distributor.Therefore,the liquid film stability of the new type liquid distributor is better;the liquid film stays longer in the heat exchange tube and the heat transfer effect is better.