Analysis on flow and heat transfer performance of SCO2 in airfoil channels with different fin angles of attack

Abstract

As an important component of the supercritical carbon dioxide (SCO2) Brayton cycle system, the performance of the printed circuit heat exchanger (PCHE) has a significant impact on the efficiency and compactness of the whole system. It is important to investigate the effect of airfoil fin angle of attack on the flow and heat transfer performance of SCO2 in the channels of airfoil fin PCHEs. A three-dimensional numerical model is developed and the thermal-hydraulic performance of channels with different airfoil fin angles of attack is compared. The results show that channels with consistent distribution of the airfoil fins with angles of attack of 15°–25° and channels with inconsistent distribution of the airfoil fins with angles of attack of 20°–30° have enhanced heat transfer capacity. This improvement can be attributed to the changes in the flow behavior of the SCO2, increases of the turbulent kinetic energy, changes of the thermal properties of the SCO2 and the enhanced synergy of velocity and temperature gradient fields. And the flow performance of the PCHE channel gradually reduces with increasing fin angle of attack. And the channel with the airfoil fins whose angle of attack is 15°–25° has the best overall performance.