In-tube cooling heat transfer of supercritical carbon dioxide. Part 2. Comparison of numerical calculation with different turbulence models

Major difficulty in the numerical calculation of heat transfers of supercritical carbon dioxide is the proper selection of the turbulence model. Because the thermophysical properties significantly depend on temperature and pressure, conventional turbulence models proposed for constant-property conditions might not be valid for supercritical pressure conditions, and therefore need to be analyzed carefully. Here, four turbulence models were applied to both heating and cooling conditions of supercritical carbon dioxide, and the simulation results of heat transfer coefficient were then compared with experimental data. The JL model (low Reynolds number k–ε model by Jones and Launder) showed the best agreement with the experimental data. The three other models (a mixing length model by Bellmore and Reid, and two other low Reynolds number k–ε models, respectively, by Launder and Sharma and by Myong and Kasagi) should be re-examined because they use a dimensionless distance from the wall y+. The turbulent Prandtl number did not significantly affect the calculation results of heat transfer coefficient.