The role of jet-to-crossflow velocity ratio on convective heat transfer enhancement in the cooling of discrete heating modules

Abstract

• This study aims to evaluate the effects of the momentum contribution of the jet flow on heat transfer and thermohydraulic performance in the cooling of blocks simulating electronic components with crossflow and jet flow. • The jet nozzle used in addition to the cross flow increases not only the thermal enhancement factor of the first block, but also the thermal enhancement factor of all blocks. • The contribution of the jet to the improvement in heat transfer is greater than the increase in pressure drop. Thus, the jet impingement cooling appears to be a good alternative for electronics cooling. This study aims to investigate the role of jet-to-cross flow velocity ratio on convective heat transfer and flow characteristics in a channel with discrete heating modules simulating electronic components. Three-dimensional numerical simulations are performed using the finite volume method. The findings obtained for different velocity ratios of the jet-to-crossflow are compared with the reference case (crossflow solely). While keeping the crossflow velocity and the crossflow Reynolds number ( Re c = 5000 ) constant, numerical calculations are performed for six different velocity ratios ( U r = 1.0 , 2.0 , 4.0 , 6.0 , 8.0 and 10.0 ). The focus is on the role of the velocity ratio ( U r ) on the mean Nusselt number ( Nu m ) on the modules’ surfaces, the Nusselt number ratio ( Nu r ), the friction coefficient ratio ( f r ) obtained throughout the channel and the thermal enhancement factor ( TEF ). As a result of the study, it is revealed that the momentum of jet flow becomes dominant over crossflow, the influence of jet flow on convective heat transfer increases, and the thermal enhancement factor increases depending on the increasing jet-to-cross flow velocity ratio.