Abstract:

Due to good environmental characteristics and excellent thermodynamic properties, CO₂ is considered as an ideal alternative refrigerant. Compared with the traditional refrigerant, CO₂ flow boiling heat transfer characteristics is very different. However, the existing heat transfer correlations are based on their respective test data fitting, because the data points are too less and the range of variable parameters is limited, the predicted results are very different. To establish the CO₂ tube flow boiling heat transfer in a more comprehensive database, compare and analyze different heat transfer models, it is of great significance for deep understanding of the boiling heat transfer characteristics of CO₂ in tube and study more accurate heat transfer correlation. There are six correlations analyzed by using 4040 experimental data points of CO₂ flow boiling heat transfer from 24 references, the study found that for Fang (2013) correlation minimum error is 10.6%, and draw the variation of gas and liquid Reynolds number with pipe diameter, and the change of gas and liquid Reynolds number scatter plot and the plot of Nusselt number change with Bond number, it can provide insight into the CO₂ tube flow boiling heat transfer characteristics and the future research a new type of heat transfer correlations for more accurate to provide the reference.

Key words: carbon dioxide, flow boiling, dry, heat transfer coefficient

摘要：

CO₂由于良好的环境特性和优良的热力学特性，被认为是一种理想的替代制冷剂。与传统制冷剂相比，CO₂有着十分不同的流动沸腾换热特性。然而现有的换热关联式都是基于各自的实验数据拟合得出，由于数据点太少和变量参数范围受限导致关联式的预测结果大相径庭。所以建立更加全面的CO₂管内流动沸腾换热数据库对不同换热模型进行对比分析，对于深入了解CO₂管内流动沸腾换热特性和研究更加准确的换热关联式具有重要意义。通过从24篇文献中搜集的4040个实验数据点对6个CO₂的管内流动沸腾换热模型进行对比分析，发现Fang（2013）关联式误差最低为10.6%，并绘制了气液相Reynolds数随管径的变化，气液相Reynolds数的变化的散点图以及Nusselt数随Bond数变化的趋势图，可为深入了解CO₂管内流动沸腾换热特性和将来研究更加准确的新型换热关联式提供参考。

关键词: 二氧化碳, 流动沸腾, 干涸, 传热系数