Abstract: A two-fluid model and a homogeneous model for trans-critical carbon dioxide in a short tube were developed.Both inter-phase velocity slip and temperature difference were taken into account in the two-fluid model, but not in the homogeneous model. Experimental results on the mass flow rate were used to verify these two models.The results showed that for the two-fluid model the deviation of 90% model prediction was under ±20%.Furthermore it could give reasonable pressure distribution along the tube length.The homogeneous model could also give reasonable prediction results,and not seriously lower than measured results while disregarding the non-equilibrium characteristics.The non-equilibrium flow characteristics of trans-critical carbon dioxide in the short tube are not obvious which could also be verified by small inter-phase velocity slip and temperature difference.Finally, this phenomenon was given theoretical explanation.

摘要： 建立了跨临界CO₂在短管内流动的两流体模型和均相流模型.两流体模型考虑了汽液两相间的速度滑移和温度差异，而均相流模型则认为汽液两相的速度和温度相同.分别用两种模型进行了计算，并与实验数据进行了对比.结果表明：两流体模型90%的流量计算值与实验值偏差在±20%以内，并能合理预测压力的沿程分布;均相流模型对流量的预测结果与两流体模型接近，并未因忽略非平衡特性而严重偏低.另外，汽液两相温度差异和速度滑移的分布计算结果也证实了短管内跨临界CO₂流动的非平衡性并不显著.本文从理论上对此现象进行了解释.