水冷式表冷器工况判别方法剖析

Analysis of Method on Judging Work Conditions of Water-cooled Surface Air Coolers

指出国内目前使用的水冷式表冷器工况判别方法是无效的,因为它不能判别干、湿、半干半湿三种工况。介绍了 ASHRAE 推荐的和卡尔波斯提出的工况判别方法。通过理论推导,证明两者实质是等价的,表达形式的不同是由于前者对干湿表面分界线上的换热分析应用的足湿表面的换热规律,而后者应用的是干表面的换热规律。通过在表冷器两侧需增足够大的换热面积,阐明了它们的判别原理。根据国内目前使用的实验方法,指出国内以选用卡尔波斯提出的方法为宜,并给出了其在做校核性计算时的使用程序。结合卡尔波斯提出的工况判别方法,对目前的半干半湿工况热力计算方法进行了改进。

It is pointed out that the present domestic Method of Judging Conditions （MJC） of water-cooled surface air coolers is invalid because it cannot discern whether the job condition is fully wetted, partially dry, or completely dry cooling condition. MJC of ASHRAE and one of Karps through theoretic analysis. These difference in outward heat transfer of the dry-wet boundary condition, and are introduced and are proved that they are the same in essence form is that the former uses dehumidifying cooling theory in the the latter has sensible cooling theory. Through adding enough heat-exchange surface to air cooler imaginary, judging work conditions correctly are explained. According to the present domestic testing method, MJC of Karps is more adaptive in China and steps to use MJC of Karps in checking calculation are put out. Based on MJC of Karps, the present calculation method of partially dry cooling condition is advances.