A novel structure tube for supercritical CO2 turbulent flow with high non-uniform heat flux

Abstract

Supercritical CO2 has been a promising alternative working medium in coal-fired power plants, high-temperature solar power systems, and fuel cells. In these cases, supercritical carbon dioxide is in a round tube under high temperature and pressure with high non-uniform heat flux. In this study, a novel structure tube is proposed by optimizing the coupling between circumferential heat flux and tube thickness on the heat-absorbing side to improve its comprehensive performance. A thermal-fluid-mechanical coupling model was developed. The novel structure can reduce maximum temperature and temperature difference effectively for the half-cycle uniform and non-uniform heat flux. The maximum thermal stress decreased by 23 and 29% and the maximum temperature decreased by 29.6 and 24.8 K for half-cycle uniform and non-uniform heat flux when the Eccentricity increased from 0 to 0.4. A comparison was made between the proposed structure, thin-walled tube, and traditional tube. Results showed that the performance of the proposed tube is the best. The maximum temperature decreases by approximately 55 K compared with the traditional and thin-walled tubes. The maximum equivalent stress of proposed tube is the smallest. Furthermore, the structure will improve the safety and economics of the tube.