Measurements of heat transfer coefficients from supercritical fluid flowing in vertical mini channels with constant wall temperature

Abstract

Currently, efficient heat transmission for compact electronic elements is an essential matter. It needs a heat sink with a liquid cooling scheme that meets these demands as much as feasible. The dimensions of 50.8 × 40.6 × 5.5 mm were adopted for features of heat transfer as well as the fluid flow of supercritical CO2 in the heat sink in this study. The adopted pressures, tem-peratures, and mass velocity ranges were 7.5 to 12 MPa, 35 to 50oC, and 100 to 500 Kg/m2s, respectively, wherein the CO2 cooled under these conditions. The factors of heat transfer, the pressure at levels of local as well as medium degree were determined under these conditions. The medium temperature of CO2 in the adjacent significant point area increased, the pressure decreased and the medium temperature movement factor augmented dramatically. It was also noted that the medium temperature movement factor peaked at the pseudo-critical tempera-ture. However, the maximum temperature movement factor declined increased pressure. Fur-thermore, in contrast to the pressure factor, it was revealed that mass velocity and temperature movement factor had a direct relationship. Using the obtained data, a novel correlation mech- anism for limited convection of super-critical CO2 in regular multi-port micro tubes based on chilling conditions was constructed using the obtained coefficients in this study.