CO2微通道气冷器的流场分解模拟及实验验证

为了研究CO₂流量分配不均匀度对气冷器流动特性和传热特性的影响，建立了跨临界CO₂制冷系统的微通道气冷器分解模型. 实验结果表明：随着CO₂制冷剂质量流量由110 kg/h增大到470 kg/h，扁平管内最大流量不均匀度由97% 降低到18%,流量是影响不均匀度的重要因素；流量分配不均度对CO2微通道气冷器的流动特性影响明显，而对传热特性影响较小. 比较了不同工况下相应的模拟结果与实验数据,平均换热系数误差为4.82%~38.25%，摩擦系数误差为6.09%~26.65%.

Decomposing Numerical Simulation and Experimental Verification of Carbon Dioxide Micro-channel Gas Cooler

In order to investigate the effect of CO2 mal-distribution in micro-channel on the flow and heat transfer characteristics of gas cooler,decomposing numerical model of micro-channel gas cooler in trans-critical CO2 system was constructed and experimentally verified.The results show that the maximum flow rate nonuniformity decreases from 97% to 18% as total inlet flow rate of CO2 increases from 110 kg/h to 470 kg/h,meaning that the flow rate is the critical factor of mal-distribution.The mal-distribution of refrigerant flux has a significant effect on the flow characteristics of micro-channel gas cooler.While to the heat transfer characteristics,its effect is not obvious.The numerical results were compared with the experimental data under different running conditions.The inaccuracy of average heat transfer coefficient ranges from 4.82% to 38.25%,and the inaccuracy of friction coefficient ranges from 6.09% to 26.65%.