Review of correlations of flow boiling heat transfer coefficients for carbon dioxide

摘要

Carbon dioxide (CO_2) has quite different flow boiling heat transfer characteristics from conventional refrigerants due to its much higher reduced pressures that make its thermo-dynamic and transport properties very different. There were some studies evaluating the correlations of flow boiling heat transfer coefficient for CO_2. However, either the number of correlations covered or the number of data used was limited, resulting in inconsistent conclusions. This work presents a comparative review of existing correlations for flow boiling heat transfer coefficient of CO_2. There are 34 correlations analyzed and evaluated using 2956 experimental data points of CO_2 flow boiling heat transfer from 10 independent laboratories. The Fang (2013) correlation performs best with a mean absolute deviation of 15.5%. The evaluation analysis sets a channel transition criterion for flow boiling heat transfer of CO_2. Several topics worthy of attention for future studies are identified.