二氧化碳微通道蒸发器压降特性的模拟验证

分析二氧化碳微通道蒸发器的物理结构及二氧化碳两相段及过热段的流动特性，基于有限元分析法，采用分段研究的方法建立微通道二维分布参数模型。研究各参数对二氧化碳在微通道中流动特性的影响，根据模拟结果可得压降主要发生在蒸发器入口经集流管进入扁管处，二氧化碳在过热段压降远小于两相段压降。蒸发压力对扁管内的压降影响很小，随着二氧化碳质量流率增大，压降增大，两相区与过热区分界线右移。对比分析模拟与实验结果，误差在10%之内，验证所建立数学模型的合理性。

Simulate verification of CO2 microchannel evaporator pressure drop

This research aims at analyzing the physical structure of CO₂ microchannel evaporator and the fluidity of CO₂ at two-phase segment and overheat segment. Based on the finite element analysis and the method of segmentation study, the researcher established the microchannel two-dimensional distribution model. The model simulation show that pressure drop mainly happens at the junction of header pipe and flat tube. Pressure drops more at overheat segment than at two-phase segment. Influence of evaporating pressure to the pressure drop of CO₂ at flat tube is small. Boundary line between two-phase segment and overheat segment shifts right, when the CO₂ flow rate increases and the pressure drop grows. Comparative analysis of simulation and experimental results show the error is within 10%, which verifies the reliability of the established model.