Similarity between Cooling Heat Transfer in the Sub-and Super-critical Pressure Regions

Abstract

Experiments on the natural convective heat transfer of the carbon dioxide to a vertical cooling cylinder were carried out both in the sub-and super-critical pressure regions near the critical point and the fluid flow around the cylindrical heat transfer surface were observed. In the subcritical region, experiments on the condensation were conducted for both saturated and superheated vapors, and in the supercritical pressure region, experiments on the heat transfer from fluid being in the pseudocritical temperature and beyond the pseudocritical temperature have been done. In the supercritical region, the "liquid-like" fluid layer was observed and also heat transfer coefficient showed a very similar tendency to the condensation heat transfer. Thus, similarities of the fluid flow and the heat transfer between the sub- and super-critical pressure regions was found.