新型蒸发式冷凝器换热性能理论及实验研究

Theoretical and Experimental Study on Heat Transfer Performance of New Evaporative Condenser

本文对横管式蒸发式冷凝器的传热传质性能建立了理论模型,研究了风量、喷淋水量对紧凑型横排管结构蒸发式冷凝器换热性能的影响。结果表明:总传热系数与管内对流换热传热系数、管壁与管外喷淋水传热系数及喷淋水与空气等效传热系数相关,管内对流换热环节、管外对流换热环节及喷淋水与空气热质交换环节的热阻占比分别为14.14%、22.13%和63.76%,喷淋水与空气换热环节热阻占比最大;相同喷淋水量、不同风量条件下,喷淋水与空气等效传热系数随着风量的增加而增大,且增长率逐步减小;相同风量、不同喷淋水量条件下,喷淋水与空气等效传热系数随着喷淋水量增加而基本保持不变。实验结果表明风量为22540.3 m^(3)/h,喷淋水量48.86 m^(3)/h时,蒸发式冷凝器的换热性能最优。

The theoretical model of heat and mass transfer performance of the horizontal tube evaporative condenser is established,while the influence of the amount of air and spraying water on the heat transfer performance of the horizontal tube evaporative condenser is studied.The results show that the total heat transfer coefficient is related to the convective heat transfer coefficient in the tube,the convective heat transfer coefficient on the outer wall of the tube and the equivalent heat transfer coefficient between spray water and air.The thermal resistance ratios of convective heat transfer in the tube,convective heat transfer outside the tube and heat and mass exchange between spray water and air are 14.14%,22.13%and 63.76%,respectively.The heat resistance ratio between spray water and air is the largest.The equivalent heat transfer coefficient between spray water and air increases with the increase of the amount of air under the same spray water quantity,while the growth rate decreases gradually.The equivalent heat transfer coefficient between spray water and air basically remains unchanged with the increase of spray water volume under the same amount of air.The experimental results show that the evaporative condenser has the best performance in heat transfer when the air flow reaches 22540.3 m^(3)/h and the spray water reach 48.86 m^(3)/h.