Simulation on the evaporative cooling characteristics of humid air-water outside staggered tube bundles

Abstract

In this paper, a new model was established to investigate the evaporative cooling characteristics of humid air-water outside staggered tube bundles. The Euler Lagrange method was adopted based on the coupling between DPM (discrete phase models) and WFM (wall film models). The formation of spray water film by spray water droplets and the separation process of that are considered on the tube bundle walls in this model. The model reliability was verified by experimental data in literatures. Meanwhile, the process was simulated on the evaporative cooling of humid air-water outside staggered tube bundles. The results showed that the evaporation process of spray water outside staggered tube bundles is mainly concentrated near the wall and the wake area of humid air outside tube bundle. The evaporation rate of spray water is the lowest at the circle angle range of tube bundle which is − 45° – 45°, while it is the highest near the circle angle of ± 115°. To strengthen the convection between humid air and mainstream air in the area of tube bundle (circle angle is in the range of − 45° – 45°), the water vapor concentration should be reduced and the evaporation characteristics should be improved in this area. The evaporation rate of spray water can be negatively affected by relative humidity outside the staggered tube bundles. The secondary entry of high humidity air should be avoided from the exhaust port into the air inlet. The spray water flow has a positive effect on improving the evaporation rate of spray water. The above results provide guidance for the design of evaporative cooling characteristics of humid air-water outside staggered tube bundles.