To analyze the convection heat transfer characteristics of supercritical carbon dioxide(S-CO_2) in concentrating solar power receiver at high temperature and with non-uniform wall heat flux distribution

a threedimensional numerical model is established using ANSYS Fluent software for a multi-tube absorber. The radiation and convection heat transfer between the absorber and environment are both considered. The influences of three wall heat flux distributions on the convection heat transfer and flow characteristics of S-CO_2 are analyzed. The numerical results show that

radiation and convection heat transfer between the absorber and the environment have significant effects on wall temperature of the absorber. Compared with none radiation and convection heat transfer between the absorber and environment

the maximum wall temperature reduces by 6.84%. Among three wall heat flux distributions

the outlet temperature and maximum wall temperature of the absorber are both the highest for the half non-uniform heated wall with circumferential cosine and axial Gauss. Moreover

its maximum wall temperature is 353.4 K higher than that of the half uniform heated wall. Although the non-uniform heat flux distribution on the wall has insignificant effect on the flow distribution uniformity in the absorber

it can reduce the influence on the fluid temperature deviation in each tube caused by uneven flow distribution.