Abstract: 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.

Key words: liquid distributor, falling film evaporator, wetting rate, liquid film thickness, heat transfer