Numerical Investigation on Conjugate Heat Transfer of Supercritical CO₂ in a Horizontal Double-Pipe Heat Exchanger

The special fluid flow and heat transfer characteristics of supercritical CO₂ in a horizontal double-pipe heat exchanger have been numerically investigated. The AKN k-epsilon model was selected to model the turbulent flow and heat transfer of supercritical fluid. In conjugate heat transfer process, there exists obvious heat transfer deterioration on the top wall for horizontal flow. The region of heat transfer deterioration expands with the increased G_Shell or T_Shell,0, and the influence of T_Shell,0 on conjugate heat transfer is greater than that of G_Shell. The high-temperature fluid will gather near the top region. The intensity and position of the secondary flow can represent the turbulence heat transfer. When the supercritical fluid temperature is much higher than T_pc, buoyancy force can be omitted, but it can not been neglected even under relatively high mass flux.