【摘要】 毛细管作为一种膨胀装置在小型制冷系统和热泵系统中得到了广泛的应用。尽管毛细管具有简单的几何形状，其中的绝热流动却是极其复杂的。本文对模拟异丁烷（R600a）在毛细管中绝热流动的均相流动模型和分离流模型进行了对比研究。研究了不同的摩擦系数和两相黏度关系式的组合以及亚稳态流动对流动特性的影响。结果表明，采用分离流模型时预测的质量流量较低。分离流模型在预测超过2 kg·h^-1的质量流量时表现较好，Colebrook摩擦系数关系式结合Dukler或Mc Adams黏度关系式得到的偏差较小，在忽略和考虑亚稳态流动的情况下分别为5.43%, 5.49%和5.44%, 5.43%。此外，采用Bittle和Pate摩擦系数和Dukler黏度关系式的均相流模型在低于2 kg·h^-1的质量流量范围内具有最高的精确度，不考虑亚稳态流动情况下的平均误差为4.12%，考虑亚稳态流动情况下的平均误差为3.37%。更多还原

【Abstract】 Capillary tubes have been widely used as expansion devices in small-scale refrigeration and heat-pump systems.However, adiabatic flow through a capillary tube is extremely complicated, despite its simple geometry. This work presents a comparative study on the homogenous flow model and separated flow model, which were used to simulate the flow of isobutene（R600a） through adiabatic capillary tubes. The influence of different combinations of friction factor and two-phase viscosity correlations, and the effect of metastable flow on the flow characteristics were investigated. The predicted mass flow rate was lower when the separated flow model was used. The separated flow model performed better in predicting a mass flow rate over 2 kg·h^-1. The Colebrook friction factor correlation combined with the Dukler or Mc Adams viscosity correlation yielded smaller deviations of 5.43%, 5.49% and 5.44%, 5.43% when ignoring and considering the metastable flow, respectively. Additionally, the homogenous flow model adopting the Bittle and Pate friction factor and Dukler viscosity correlations achieved the highest accuracy with a mass flow rate under 2 kg·h^-1. The mean error was4.12% in the case without metastable flow, and 3.37% in the case with metastable flow.更多还原