Thermo-hydraulic performance of interconnected mini-channels with periodic boundary layer interruption

Abstract

Abstract Printed circuit heat exchangers require channel geometries that provide effective heat transfer without excessive hydraulic resistance. This study numerically investigates the effect of the interconnection ratio, Sy/Py , on the thermal-hydraulic performance of a staggered mini-channel with periodic interconnection zones. Three configurations, Sy/Py = 0.25, 0.5, and 0.75, were evaluated over Re = 2700–7900 using three-dimensional RANS simulations with the RNG k-ε model and Enhanced Wall Treatment. Increasing the interconnection ratio strengthened transverse flow between adjacent channels, with the transverse velocity reaching approximately 0.4 m/s at Sy/Py = 0.75. However, stronger transverse flow was accompanied by increased hydraulic resistance. Increasing Sy/Py from 0.25 to 0.5 increased the friction factor by approximately 42%. The configuration provided the highest heat-transfer performance, with a Nusselt number approximately 16% higher than that of Sy/Py = 0.25. A further increase to Sy/Py = 0.75 did not improve heat transfer because larger low-velocity recirculation regions reduced effective convection near the heated surface. Thermal enhancement factor analysis showed that Sy/Py = 0.25 provided the highest overall thermo-hydraulic performance because of its lower hydraulic resistance. These results demonstrate that the interconnection ratio controls the balance between transverse flow exchange, heat-transfer enhancement, and pressure loss.