大焓差蒸发冷却器传热性能试验研究

The Heat Transfer Performance Experimental Study on the Large Enthalpy Difference Evaporative Cooler

为增大蒸发冷却过程中空气进、出口焓差,提高蒸发冷却装置换热效率,提出一种大焓差蒸发冷却水冷冷凝装置,由盘管与填料组成的蒸发冷却器,水槽与肋片盘管组成的水冷冷凝器两者串联而成。在此基础上搭建大焓差蒸发冷却器传热性能试验台,通过测试喷淋水密度与空气流量对盘管内热流体出口温度和喷淋水出口温度的影响,研究蒸发式冷凝器管外水膜的传热性能。结果表明,随着喷淋水密度或空气流量的增加,喷淋水出口温度上升,盘管内流体温度下降。此外,根据实验数据回归分析,拟合出直径为12.7mm的紫铜管管外水膜换热系数与喷淋水密度关系式为:a_w=302(r÷d_0)^(0.67)

The large enthalpy difference evaporative cooling water-cooled condenser which consists of an evaporative cooler, a water tank and a water-cooled condenser is a highly effective and low consumption condensing unit. It divides the condensation zone of refrigerant vapor into a high-temperature sensible heat evaporation condensation zone and a low-temperature latent heat water-cooled condensing zone, and air enthalpy difference of import and export increase. We build a test bench for testing the thermal performance of large enthalpy difference evaporative cooling condenser, by adjusting the water spray density and air flow, to test the changes of thermal fluid flow outlet temperature in coil and the changes of spray water outlet temperature, researching on heat transfer performance of evaporative condenser pipe web of film. The results show that with the increase of spray water density, the outlet temperature of spray water rise before leveling off, the temperature of the fluid within the coil drop before leveling off. In addition, through regression analysis of experimental data, fitting the DN 12 copper tube equation between pipe web of film heat transfer coefficient and spray water density：aw=302（r/d0）^0.67.