Experimental investigation on heat transfer performance based on average thermal-resistance ratio for supercritical carbon dioxide in asymmetric airfoil-fin printed circuit heat exchanger

The discontinuous airfoil-fin printed circuit heat exchanger is a leading candidate due to its high compactness, high efficiency, and ability to endure extreme conditions. In this paper, an unusual asymmetric airfoil-fin heat exchanger is experimentally investigated using the supercritical carbon dioxide and water experimental system. The effects of working parameters and flow direction on the heat transfer performance are analyzed based on the average thermal-resistance ratio. Meanwhile, the effects of flow directions on the comprehensive performance are quantitatively evaluated. Compared with the overall thermal resistance, the average thermal-resistance ratio is more sensitive in evaluating the heat transfer performance. The reverse flow hardly improves the heat transfer, while significantly amplifies the pressure drop. Compared with the reverse flow, when the bulk temperature of CO 2 is 38 °C, 41 °C and 47 °C, the comprehensive performance of forward flow increases by 6.1%, 4% and 1.8%, respectively. Finally, the unified heat transfer correlation for two opposite flow directions is proposed within applicable ranges. • One type of asymmetric airfoil-fin heat exchanger is proposed and tested. • Average thermal-resistance ratio is sensitive to the heat transfer. • Effect of flow direction on the comprehensive performance is evaluated. • Unified heat transfer correlation for two opposite flow directions is proposed.