CO_2微通道气体冷却器压降与传热特性研究  

CO_2 Pressure Drop and Heat Transfer Characteristics in Micro-Channel Gas Cooler

作　　者：李程[1] 巫江虹[1] 崔晓龙 文光彩 何冰强[1,3] 陈基镛 

机构地区：[1]华南理工大学机械与汽车工程学院,广州510641 [2]广州万宝集团公司,广州510620 [3]广东水利电力职业技术学院,广州510635 [4]宝马利汽车空调设备有限公司,广东阳江529565

出　　处：《西安交通大学学报》2010年第9期48-53,共6页Journal of Xi'an Jiaotong University

基　　金：广东省教育厅产学研项目(2009B090300380);广州市科技计划项目(2007Z2-D0231)

摘　　要：在微通道平行流式气冷器内进行了CO2的压降和换热特性实验研究,探讨了跨临界CO2循环换热过程中制冷剂质量流量、系统压力对气冷器换热性能、进出口压降的影响.实验结果表明:在接近临界温度时,CO2物理性能受压力和温度的影响较大,换热系数是远离临界区的7～9倍;随着CO2质量流量的提高,微通道管内流体Re相应提高,而较高的Re又使得湍流扩散率、管内温度梯度增大,同时在制冷剂入口附近的微通道换热器高温区域面积增大,表明当系统压力相同时,制冷剂入口温度随CO2质量流量的增加而增大.在一定的质量流量或压力下,存在着一个最佳的压力或质量流量,使得气冷器进出口压降达到最小.随着Re增加,气冷器的CO2压降关联式的预测精度均有所提高,为此提出了新的换热关联式和压降关联式.The pressure drop and heat transfer characteristics of a micro-channel gas cooler were studied with the trans-critical CO2cycle.The influence of the CO2mass flowrate and the pressure difference of the inlet and the outlet on the heat transfer performance of the gas cooler was experimentally investigated.The results show that the thermal physical properties of carbon dioxide were affected significantly by the fluid pressure and temperature near the critical temperature,and the heat transfer coefficient was 7-9times that at the other area far from the critical area.The Reynolds number in the micro-channels increased with the increase in CO2mass flowrate,leading to the increase in the turbulent diffusion rate and the increase in the temperature gradient inside the tube.The region edge with relative higher refrigerant temperature near the entrance extended,indicating that the inlet refrigerant temperature increased with the CO2mass flowrate at the same system inlet pressure.At a certain mass flowrate or inlet pressure,there was an optimum pressure value or CO2mass flowrate value to generate a minimum pressure drop in the system.The results obtained by correlation formulas were compared,and then a new heat transfer correlation and a new pressure drop correlation were proposed.

关 键 词：二氧化碳制冷 微通道 压降 气体冷却器 

分 类 号：TB657.5[一般工业技术—制冷工程]