半室外环境两相流低压雾化降温数值分析

Numerical analysis of cooling process in two-phase flow by low pressure atomization in semi-outdoor environment

为了改善夏季半室外空间的环境舒适度,研究了一种节能环保的两相流低压雾化降温技术.利用CFD软件FLUENT对其降温进行了分析,结合半室外环境的气象条件,获得了20μm和40μm两种粒径液滴对降温效果的影响规律.根据半室外环境中的人群活动特征,对其降温效果进行了初步分析.结果表明:在半室外环境中,采用两相流低压雾化降温可以达到较好的降温效果,在1.7 m及1.2 m等两种人体感知区域范围内,采用20μm和40μm两种粒径的细水雾最高温度降幅可达3.5℃,有明显的降温感觉;采用两相流低压雾化降温,不会引起局部环境中相对湿度的明显增加,人体不会感觉到闷热潮湿.两种粒径的细水雾均能完全蒸发,降温增湿的幅度和范围基本相同,没有明显区别.

In order to improve the comfort of semi-outdoor environment in summer,the cooling in two-phase flow by low pressure atomization is presented.It is an energy efficient and environmentally benign technology.The cooling process is simulated by using CFD code FLUENT.According to the climate condition in the semi-outdoor environment,the simulations are conducted for different cooling effect,each with droplet diameters of 20 micrometers and 40 micrometers.According to the character of human activity in semi-outdoor environment, the pilot analyses of the cooling effect are made. The results revealed that the evident cooling effect of two-phase flow by low pressure atomization in semi-outdoor environment could be achieved. In the perception zone of human body, the evident cooling effect is made ; the cooling up to 3.5 centigrade is attained in the numerical simulation. The relative humidity in local environment does not increase evidently during the cooling process in two-phase flow by low pressure atomization, human body will not sense the dampness and swelter. All of these two types of fine water mists could evaporate, the areas of cooling and humidifier are almost the same.