关键词: 竖管, 蒸发式冷凝器, 传热性能, 强化, 下降液膜

Abstract:

In this paper, a device for testing the performance of evaporative condenser with a vertical plexiglas tube was built up, and the influences of the inlet velocity, the tube height, the heat-transfer temperature difference and the spiral insert on the heat transfer performance of the proposed evaporative condenser were investigated. It is found that, at a certain temperature difference, the relationship between the Sherwood number and the Reynolds number of the falling liquid film is approximately linear, and takes on the form of a quadratic curve in the condition of spiral inserts, that an inlet velocity under 3.3 m/s may prevent the liquid from flooding, that there is an optimal tube height range of 0. 8 to 0. 9 m where the outlet air possesses the largest relative humidity, and that the heat transfer is greatly enhanced and the Sherwood number increases by more than 15% when the ratio of spiral insert diameter to tube diameter ranges from 0. 06 to 0. 29.

Key words: vertical tube, evaporativecondenser, heat transfer performance, enhancement, falling liquid film