进风条件对平行流冷凝器性能的影响

Effect of Different Airflow Conditions on Performance of Condenser

摘要:

以平行流冷凝器为研究对象，采用考虑制冷剂侧流量分配的数学模型，研究了几种实际进风条件对冷凝器性能及制冷剂侧流量分配特性的影响，这些进风条件包括：前端遮挡、前置设置散热器和单双冷却风扇单双配备共三类.研究发现：在50%遮挡率下，中间遮挡方式对冷凝器的性能衰减最多，换热量减少了47.9%，压降增加了335.5%；不同遮挡方式对制冷剂侧流量分配有不同的影响，格栅遮挡造成的制冷剂侧流量分配不均匀程度最大.前置散热器造成的局部进风速度降低与温度升高可导致冷凝器换热量减少24.1%，压降增加80%，前置散热器只对第二流程的制冷剂侧流量分配不均匀程度有明显的影响.总风量不变时，单、双风扇情况下的进风不均匀对整体换热与压降的影响不明显，但是各个流程制冷剂侧流量分配不均匀程度都有明显增加.

Abstract:

A numerical thermal-hydraulic model considering the mal-distribution of refrigerant-side is used to investigate a four passes parallel-flow condenser. The influence of different airflow conditions on the performance and refrigerant distribution characteristic of this condenser is given. The related airflow conditions are inlet blockage, front radiator and different number of cooling fans. The results are as follows. At 50% blocking rate, the middle blocking mode makes the most deterioration of the performance of the condenser, heat transfer rate decreases 47.9% and refrigerant pressure drop increases 335.5%. The different blocking modes have different effects on the flow distribution of the refrigerant side, and the unevenness of the refrigerant distribution caused by grille block is the largest. The partial air velocity reduction and temperature increase caused by a front radiator results in 24.1% decrease in heat transfer and 80% increase in refrigerant pressure drop of the condenser. The front radiator only influences the refrigerant flow distribution of the second pass. When total air flow is constant, different number of cooling fans have little effect on heat transfer and pressure drop, but the unevenness of the refrigerant distribution is obviously increased.