A steady state distributed parameter model for the microchannel evaporator applied in a transcritical carbon dioxide air-conditioning system was established using the FEM method. Different models of heat transfer at the refrigerant-side were compared and analyzed, and a modified heat transfer correlation was proposed. Moreover, characteristics of heat transfer and flow were analyzed under both dry and wet conditions considering the pressure losses at the inlet and outlet of the header of the evaporator. The simulation results are in reasonable agreement with the experimental data. The average relative errors for cooling capacity and refrigerant-side pressure drop are less than 8. 2% and 10% , respectively. It is likely that the present model may be used to analyze and design CO2 microchannel evaporators.%采用有限元分析方法为跨临界CO2空调系统的微通道蒸发器建立了二维分布参数仿真模型,比较分析了适用于不同制冷剂侧的换热关联式,并为此提出了一种修正的换热关联式,以期为微通道蒸发器模型能够获得很好的预测结果.模型中考虑了干、湿工况以及制冷剂进出集液管产生的压力损失对制冷剂侧换热和流动特性的影响.对比分析得出:微通道蒸发器的制冷量和压降在制冷剂侧仿真、实验的相对误差分别小于8.2％和10％,表明所建模型可作为CO2微通道蒸发器的优化设计的理论依据.
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