Numerical Analysis of the Thermal-Hydraulic Performance of Supercritical Liquefied Natural Gas in Airfoil Fin PCHEs

As a novel, compact, and efficient plate-fin heat exchanger, the Printed Circuit Heat Exchanger (PCHE) is a prospective candidate for liquefied natural gas (LNG) vaporization at low-temperature and high pressure. Generally, the airfoil fin PCHE has better thermal-hydraulic performance than the zigzag channel PCHE. In this study, the thermal-hydraulic performance of supercritical LNG in PCHEs with different airfoil fin types and arrangements is investigated by numerical simulations. First, the effects of six different airfoil fin types, NACA0010, NACA0020, NACA0025, NACA0030, NACA 0040, and NACA 0050, on the thermal-hydraulic performances were studied. The results show that NACA0025 has the best comprehensive heat transfer performance. Then, the effects of the airfoil fin arrangement's staggered, vertical, and horizontal pitch on thermal-hydraulic performance were investigated. The results show that the optimal values of the dimensionless number for staggered and vertical arrangements are 1 and 4, respectively. The comprehensive performance does not change much when the dimensionless horizontal pitch number exceeds 3.0. Finally, the thermal-hydraulic performance of uniformly distributed, three front sparse and rear dense, and three front-dense and rear-sparse distributed airfoil fins was investigated. The results show that the front-dense and rear-sparse airfoil fins enhance and the front-sparse and rear-dense airfoil fins reduce the comprehensive performance compared to the uniform arrangement. The results show that a denser arrangement of airfoil fins near the quasi-critical point can improve the comprehensive performance while keeping the number of airfoil fins constant.