基于气液分离原理的强化换热器研究

Research on enhanced heat exchanger based on vapor-liquid separation principle

气液两相流广泛存在于换热设备中,通过对管内制冷剂换热过程以及流型流态的分析得出在冷凝过程中,液滴刚生成的时候管内换热系数最高,蒸发过程中则是环状流换热系数最高。为了实现冷凝过程中液体快速排走提出了减薄液膜实现强化换热的气液分离技术,近些年来引起了广泛的研究和应用。创新地提出了一种可以应用于翅片管换热器的蜂窝状气液分离结构,利用仿真计算软件对蜂窝状分离结构的气液分离过程机理进行研究,同时利用Coildesigner中经验公式对其进行校核,确定了模型的准确性和可靠性,最终确定蜂窝状气液分离结构的参数。研究可以实现气液分离效率89%以上,同时装备了蜂窝状气液分离结构的翅片管式换热器,对比于传统翅片管式换热器,可以实现压降损失降低8.08%,换热量提升6.22%。

Vapor-liquid two phase flow is widely used in heat exchanger.Through the analysis of the heat transfer process and flow pattern of refrigerant in the tube,it is found that during the condensation process,the heat transfer coefficient in the tube is the highest when the liquid droplet is just generated,while during the evaporation process,the heat transfer coefficient in the annular flow is the highest.In order to achieve rapid liquid removal during the condensation process,a vapor-liquid separation technology that enhances heat transfer by thinning the liquid film has been proposed,which has attracted extensive research and application in recent years.Innovatively proposes a honeycomb vapor-liquid separation structure which can be applied to finned tube heat exchangers,simulation software is used to study the vapor-liquid separation process mechanism of the honeycomb separation structure.At the same time,the empirical formulas in Coildesigner are used to verify its accuracy and reliability,and the parameters of the honeycomb vapor-liquid separation structure are ultimately determined,which can achieve vapor-liquid separation efficiency of over 89%.At the same time,a finned tube heat exchanger equipped with a honeycomb gas-liquid separation structure can achieve a pressure drop loss reduction of 8.08%and a heat transfer increase of 6.22%compared to traditional finned tube heat exchangers.