泵供液式冷风机性能模拟与实验研究

Simulation and Experimental Research on Performance of an Air Cooler with Liquid Feed Pump

本文建立了不同流程分布的冷风机模型,对各流程分布冷风机性能进行了模拟研究;采用泵供液式制冷量测试法,对以R717为工质的最优流程分布冷风机进行了性能测试。研究表明,单排管双流程布管方式能够使冷风机的性能最优;存在使冷风机制冷量最大的泵送比,在蒸发温度-25℃工况下,当泵送比为3.5时,冷风机的制冷量最大,为44.3 k W;随着蒸发温度的升高,冷风机的传热系数逐渐增大,当蒸发温度为-25℃时,传热系数为27.4 W/(m^2·K),当蒸发温度为0℃时,传热系数为34.4W/(m^2·K),提高了25.5%;随着蒸发温度的升高,冷风机的制冷量逐渐增大,当蒸发温度为-25℃时,制冷量为44.3 k W,当蒸发温度为0℃时,制冷量为64.3 k W,增大了45.15%。采用泵供液式制冷量测试法,测得在不同实验工况下,冷风机制冷量实验值比模拟值低5%左右,验证了冷风机模型的正确性。

The performance of air coolers with different flow distribution was simulated after establishing the model of air cooler evaporator with different kinds of flow distribution, and the air cooler with optimal flow distribution which adopted R717 as refrigerant was tested using the refrigerating capacity test method with liquid feed pump in this paper. The results indicate that the performance of air cooler was optimal with the flow distribution of two circuits in a single row. The refrigerating capacity was 44.3 kW at evaporating temperature - 25℃ as the pumping ratio increased to 3.5 which was the optimum value to the air cooler. The heat transfer coefficient was enhanced by 25.5% from 27.4 W/（m^2·K） to 34.4 W/（m^2·K） with the evaporating temperature varying from - 25℃ to 0℃ and the refrigerating capacity increased from 44.3 kW to 64.3 kW which achieved a 45.15% enhancement at the same range of evaporating temperature. The experimental data also verified that the cooling capacity of experimental values were approximately 5% lower than that of simulation val- ues, which indicated the validity of air cooler model.