Thermal hydraulic performance analysis of a printed circuit heat exchanger using a helium–water test loop and numerical simulations

A Printed Circuit Heat Exchanger (PCHE) is a promising candidate with excellent performance to satisfy the heat exchanger requirements of High Temperature Gas Cooled Reactors (HTGRs). These heat exchangers are composed of many micro-wavy channels, which cause an increase in both heat transfer and pressure drop. We investigated thermal-hydraulic performance of the PCHE in a helium-water condition through experimental tests and numerical simulations with horizontal and vertical arrangements. Experiments were performed in laminar region. Pressure drop and temperatures were measured during experiments at the inlet and outlet of the helium and the water sides, respectively. We obtained three-dimensional (3-D) numerical solutions with periodic boundary conditions using the computational fluid dynamics (CFD) code, FLUENT. The numerical simulation range was expanded to Reynolds number of 2500 through the 3-D CFD simulations, after the numerical solutions were validated against experimental data. A proposed Fanning factor correlation in the PCHE, in terms of Reynolds number and a correction factor, predicts the local pitch-averaged Fanning factor in the helium and the water sides in the range of less than 0.97% and 0.65%, respectively. A Nusselt number correlation with an average error of 3.589% was also developed in terms of Reynolds number and Prandtl number.