建立了CO2制冷系统中绝热毛细管一维稳态分布参数模型,以研究跨临界CO2系统中毛细管的性能和流动特性.分别采用3种不同摩擦系数关联式(Churchill、Colebrook、Bittle&Pate关联式)进行模拟和比较,研究了CO2在毛细管内的温度、压力、焓、熵及干度等的沿程分布规律.分析了管径、入口压力、入口温度和背压等4个参数对毛细管质量流量的影响,并考虑了壅塞现象.结果表明:采用Churchill和Colebrook关联式的效果较好,92％的计算值误差在10％以内,而Bittle＆Pate关联式不适用于CO2绝热毛细管计算,因为它未考虑毛细管内壁的粗糙度；背压对质量流量影响很小,即使发生壅塞,壅塞质量流量和未壅塞时的质量流量差别也不大.%A one dimension homogeneous steady model of adiabatic capillary tubes in CO2 tran-scritical refrigeration systems was established to evaluate the performance and the flow characteristics of capillary tubes. The simulation results by using three different friction factor correlations (Churchill, Colebrook, Bittle&Pate) were compared with each other. The distributions of temperature, pressure, enthalpy and entropy along the tube length were investigated. The influences of four parameters (inner diameter, inlet pressure, inlet temperature, back pressure) on the mass flow rate were explored, and the chocking phenomenon was analyzed. The results show that the Churchill correlation and the Colebrook correlation predict 92% of the refrigerant mass flow rates with an error of less than 10% while the Bittle&Pate correlation may be unsuitable for simulating the flow in CO2 capillary tubes due to its neglect of the inner wall roughness of capillary tubes. The back pressure has slight influence on the mass flow rate. In addition, the rate of mass flow without chocking is approximately equal to that with chocking.
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