Investigation of the flow and heat transfer characteristics of helium gas in printed circuit heat exchangers with asymmetrical airfoil fins

This work presents a numerical investigation on the flow and heat transfer performance of printed circuit heat exchangers with asymmetrical airfoil fins, and the influence of the arrangements, attack angles, horizontal spacings, and staggered spacings of fins are studied. Then an orthogonal experiment is designed to optimize the comprehensive performance of these printed circuit heat exchangers. Finally, empirical correlations of Nusselt number and friction factor for these heat exchangers with the inlet Reynolds number ranging from 2000 to 10,000 are proposed based on our numerical results. The results show that the printed circuit heat exchangers with a consistent layout of fins show better comprehensive performance than those with a reverse layout. The comprehensive performance of these printed circuit heat exchangers with asymmetrical airfoil fins increases as the horizontal fin spacing and fin attack angle decrease. The staggered spacing has little influence on the comprehensive performance of printed circuit heat exchangers. In the present work, the printed circuit heat exchanger with the values of the normalized horizontal spacing, staggered spacing, and attack angles of 4, 1.0, and 1.269, respectively, exhibits the best comprehensive performances.