基于液滴碰撞模型的对喷式二次雾化海水循环冷却系统研究

Inter-spray secondary atomized cooling system refines the cooling water by means of breakup theory of droplets. Eliminating the fill makes the tower fully empty which is of far-reaching significance in circulating water with high temperature, high turbidity. In this project, the heat and mass transfer between the air and the droplets after inter-spray process. The breakup model of droplets collsion will be combined with the two-phase heat and mass transfer model between water and air. By means of the numerical simulation and experimental studies, the influences of different flow collision ways and different sea water concentrations on the cooling performance will be investigated. The research include: 1) the droplet breakup theory is coupled with the air-water two-phase heat and mass transfer model; 2) the influences of different seawater concentrations and different working conditions on the heat and mass transfer characteristics of spray cooling process. The project intends to build up a coupling model of new droplet breakup theory and heat and mass transfer model, which reveals the influencing law of inter-spray ways, nozzle layouts, seawater consentrations and working conditions of secondary spray cooling system on the sea water cooling performance. The research will also verify and improve the two-phase heat and mass transfer model based on the droplet collision theory, which provides a theoretical basis for seawater secondary spray cooling system.

对喷式二次雾化冷却系统，利用水流互击液滴碰撞破碎原理对冷却水进行细化，由于去除了填料部分，避免由水质和温度引起的填料性能下降和破坏，对处理高温、高浊度、易结垢循环水有重要意义。针对碰撞破碎的液滴在冷却过程中的传热传质问题，将液滴破碎理论与冷却系统内的气水两相传热传质模型相结合，通过对数值模拟和实验结果进行理论分析，研究不同水流碰撞方式、不同海水浓度及不同工况对冷却性能的影响，研究内容包括：1)利用液滴破碎理论对气水两相的传热传质耦合问题进行研究；2)喷雾冷却过程中海水浓度、物性及不同工况对传热传质特性的影响。本项目拟通过建立新的液滴破碎及热质传递耦合模型，揭示二次雾化冷却过程中水流互击方式、喷头布置方案、海水浓度、物性及不同工况对海水冷却性能的影响规律，验证并完善基于液滴碰撞破碎理论的气水两相传热传质耦合模型，为海水二次雾化冷却系统提供理论基础。

本项目针对碰撞破碎的液滴在冷却过程中的传热传质问题，将液滴破碎理论应用于冷却系统，通过对数值模拟和实验结果进行理论分析，研究不同海水浓度及不同工况对冷却性能的影响，取得了以下研究成果：（1）根据最新的碰撞分离模型，对水滴的对碰破碎情况进行研究，比较了淡水与海水水滴的碰撞情况；（2）根据碰撞模型，对对喷式无填料冷却塔海水水滴冷却性能进行了研究，并比较了海水与淡水的冷却情况；（3）以本文的传热传质和碰撞模型为基础，利用火用分析研究了无填料冷却塔的性能。