气体导流装置对微通道蒸发器性能的影响

Effect of Gas Diversion Device on Performance of Microchannel Evaporator

针对微通道蒸发器制冷剂流量分配不均匀造成的换热性能恶化和干蒸现象,本文搭建了双流程微通道蒸发器性能测试实验台,研究导气装置对蒸发器换热性能及扁管中制冷剂分配均匀性的影响,并与常规的双流程微通道蒸发器进行对比。结果表明:由于入口制冷剂流量不变,液相制冷剂蒸发为气体的最大相变潜热不变,导致二者换热量和传热系数差值较小,最大值仅相差0.5%和6.9%。但加导气装置后流动阻力降低,两相段长度较常规结构增幅为87.3%,过热度显著降低,风速为3 m/s时两种结构的过热度降幅为44.4%。各扁管间制冷剂分布趋于一致,均匀性得到提升,干蒸现象得到缓解。

The uneven distribution of refrigerant flow in a microchannel evaporator leads to the dry-out phenomenon that deterioraties the heat transfer performance.In this study,a dual-circuitry microchannel evaporator performance test platform was established to investigate the influence of a gas diversion device on the heat transfer performance of the evaporator and the uniformity of refrigerant distribution in a flat tube.The results showed that the maximum latent heat of the phase change was the same as that of the liquid phase refrigerant evaporation,giving rise to the small differences in heat transfer and coefficient of heat transfer between the two structures.The maximum difference was only 0.5%and 6.9%,respectively.However,the length of the two-phase section increased by 87.3%,and the superheat of the two structures decreased considerably.When the wind speed was 3 m/s,the superheat difference between the two structures was 44.4%.The distribution of refrigerant between the flat tubes tends to be consistent,the uniformity is improved,and the dry steaming phenomenon is relieved.