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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/m~2·K减少到27.9W/m~2·K,12mm管径蒸发器传热系数从27.2W/m~2·K减少到17.7W/m~2·K;16mm管径蒸发器制冷量从3.11k W升高到4.33k W,12mm管径蒸发器制冷量从2.01k W升高到4.62k W,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 flow model was established, the theoretical analysis was made on the different pipe diameter gravity recycling evaporators, and the gravity circulation refrigeration system test bench was set up to compare under different working conditions. Taking R404A as an example, the heat transfer coefficient of a 16 mm diameter evaporator decreased from 31.4 W / m ~ 2 · K to 27.9 W / m ~ 2 · K at a temperature of -25 ° C from 0 ° C to -25 ° C, and 12 mm The heat transfer coefficient of the tube evaporator was reduced from 27.2W / m ~ 2 · K to 17.7W / m ~ 2 · K; the cooling capacity of the 16mm tube evaporator increased from 3.11kW to 4.33kW, and the 12mm tube evaporator Cooling capacity increased from 2.01kW to 4.62kW, the deviation of the two from 33.6% to -6.7%, the lower the temperature in the storage, the greater the difference between the two cooling capacity. The results of the comparison show that a 16 mm evaporator is more suitable for a gravity recirculation evaporator than a 12 mm evaporator for low temperatures.