A Study on the Cooling Heat Transfer Mechanism for Supercritical Pressure CO2 in Horizontal Tube

The convective heat transfer of supercritical pressure CO2 in horizontal tube under cooling condition is numerically investigated using SST k-ω turbulent model. The effects of thermal physical properties, heat flux, tube diameter and buoyancy on the heat transfer characteristics are discussed. The results show that the temperature is asymmetric and secondary flow is generated on the cross section due to the buoyancy effect. The peak value of heat transfer coefficient appears earlier on the bottom surface than on the top surface, but its value is smaller than that on the top surface. The increasing heat flux has little influence on the peak value of heat transfer coefficient, but affects its position seriously. The larger the heat flux and the tube diameter are, the more significant the buoyancy effect is. The non-uniformity of heat transfer on the same cross section can be explained by field synergy principle. © 2017, Science Press. All right reserved.