Modified heat transfer equation for in-tube supercritical CO2 cooling

The cooling heat transfer of supercritical carbon dioxide (CO2) remains an issue unsolved, into which many experimental and formulating investigations were performed. This paper conducts a comprehensive survey and evaluation of the available experimental results and existing correlations for in-tube heat transfer of supercritical CO2 cooling. The 341 experimental heat transfer data of supercritical CO2 cooling from six papers are retrieved and assessed, among which three data sources containing 297 data are chosen for the comparative study of the existing heat transfer correlations and for the development of a new correlation and the rest three containing 44 data are put aside because they cannot be justified. The 13 existing heat transfer correlations are found, and they are evaluated with the 297 experimental data. A new correlation is developed through extensive computer tests based on the 297 experimental data and the evaluation of the existing correlations. The new one happens to be the modified form of the Fang model (X. D. Fang, Modeling and analysis of gas coolers, ACRC CR-16, Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign, 1999). It has the mean absolute relative deviation (MARD) of 8.9%, 14.6% lower than the best existing correlation.

► Proposed modified Fang model for in-tube heat transfer of supercritical CO2 cooling.
► Review of experimental data of in-tube heat transfer of supercritical CO2 cooling.
► Review of correlations of in-tube heat transfer of supercritical CO2 cooling.
► Evaluation of the 13 existing correlations with 297 experimental data.