冷库用翅片蒸发器流程优化的实验研究

Experimental Study on the Optimization of Flow Path of the Fin-tube Evaporator for Cold Storage

在0℃、-5℃、-10℃、-15℃、-18℃、-20℃六种不同工况下,依据制冷用空气冷却器国家标准,采用空气侧热平衡法对优化后的四种不同流程的冷库用翅片蒸发器性能进行对比测试。结果表明:翅片蒸发器流程布置应尽可能采用入口向下流动、出口向上流动的流程布置方式。流程数大于2时,各流程制冷剂的流量分配不均会造成有效换热面积减小,压降增大,传热系数和制冷量降低。增加翅片蒸发器的管路流程,可有效提高翅片蒸发器传热性能,但由流程布置不均引起的制冷剂分液不均对制冷量的影响远远大于增加管路流程对制冷量的影响。实验结果为改善冷风机传热性能提供了有效解决方案。

Four different flow path fin-tube evaporators for cold storage are tested under the indoor temperature of 0 ℃, -5 ℃, -10 ℃, -15 ℃, -18 ℃ and -20 ℃. According to the national standard for air cooler, the test of the performance of the fin-tube evaporator is measured with air side heat balance method. The results show that the flow arrangement of fin evaporator should be as much＂ as possible with the flow arrangement of the inlet downward flow and the upward flow of the outlet. When the flow path number is greater than 2, the unequal distribution of refrigerant brings about the reduction of the effective heat exchange area, the increase of pressure loss and the decrease of the coefficient of heat transfer and cooling capacity. As the increase of the number of flow path, the efficiency of heat transfer is enhanced. It is worth to notice that the unequal distribution of refrigerant effects on the efficiency of heat transfer of fin-tube evaporator is much great than that of the number of flow path. The experimental results provide an effective solution to improve the heat transfer performance of the fin-tube evaporator for cold storage.