Analysis of coupled heat transfer of supercritical CO2 from the viewpoint of distribution coordination

Abstract

Coupled heat transfer characteristics of supercritical carbon dioxide near the pseudo-critical point on both sides were investigated from the viewpoint of distribution coordination. According to the cosine similarity, a coordination angle was proposed to evaluate the coordination degree between heat transfer coefficients on both hot and cold sides. Distribution uniformity and heat transfer effectiveness were also discussed under different conditions theoretically and numerically. Theoretical derivation and simulations yielded the same conclusion: smaller coordination angle and better distribution uniformity correspond to higher heat transfer effectiveness when other conditions keep constant. Along this way, variable-size channel and inserting fins were suggested as two feasible solutions to optimization. This work may provide some reference for heat exchanger design and optimization with drastically variable-properties fluids.