建立均相流模型,对不同管径重力再循环蒸发器进行理论分析,并搭建重力再循环制冷系统试验台,在不同工况下进行对比.以R404A为例,在保温体内空气温度从0℃下降到-25℃情况下,16mm管径蒸发器传热系数从31.4W/m2·K减少到27.9W/m2·K,12mm管径蒸发器传热系数从27.2W/m2·K减少到17.7W/m2·K;16mm管径蒸发器制冷量从3.11kW升高到4.33kW,12mm管径蒸发器制冷量从2.01 kW升高到4.62kW,两者的偏差从33.6％降低到-6.7％,库内温度越低,两者制冷量差距越大.对比结果表明,在低温工况下16mm管径的蒸发器相比12mm管径的蒸发器更适合重力再循环蒸发器.%The homogeneous phase flow model was established to analyze gravity recirculating evaporators in the condition that different diameter finned tube heat exchangers were used respectively.The experimental device of gravity recirculating refrigeration system was set up,and the experimental results were compared with the theoretical calculation results under different working conditions.Taking R404A as an example,when the air temperature in heat insulation decreased from-5℃ to-25℃,the heat transfer coefficient of 16mm finned tube heat exchangers decreased from 31.4W/m2K to 27.9W/m2K,and the 12mm finned tube heat exchangers decreased from 27.2W/m2K to17.7W/m2K.The refrigerating capacity of 16mm finned tube heat exchangers decreased from 3.llkW to 4.33kW,and the 12mm finned tube heat exchangers decreased from 2.01kW to 4.32kW.The deviation of 16mm finned tube heat exchangers and 12mm finned tube heat exchangers of refrigerating capacity lowered from 33.6％ to-6.7％ gradually.The heat transfer coefficient and refrigerating capacity of 16mm finned tube heat exchangers were better,and more suitable for gravity recirculation evaporator when the air temperature in heat insulation was in a relatively low level.
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