Effects of abnormal gravity on heat transfer of supercritical CO2 in heated helically coiled tube

Abstract

Based on the RNG k-ε turbulence model, numerical analyses are carried out for the simulation of heating process of supercritical CO2 in the helically coiled tube in the aerospace fields. This study focuses on the influence of gravity on the supercritical CO2 heat transfer in two flow orientations: vertical and horizontal flow directions. The coupling effect of buoyancy and centrifugal force is analyzed to study the mechanism of heat transfer in helically coiled tube. Results reveal that the heat transfer coefficient is enhanced by bigger gravity force in the liquid-like region. The heat transfer coefficient exhibits a noticeable peak near the pseudo-critical temperature, but it remains almost the same in the gas-like region. Regardless of flow orientations, it has a weakening effect on the heat transfer with the low-gravity before the pseudo-critical point, whereas, it has a strengthen effect with the high-gravity. Finally, a new heat transfer correlation is proposed for the supercritical CO2 heating process covering a wide range from 0g to 6g.