Influence of aspect ratio on the thermal performance of rectangular shaped micro channel heat sink using CFD code

A numerical study has been carried out to investigate the heat transfer enhancement and fluid flow characteristics for various aspect ratios of rectangular micro channel heat sinks (MCHS). The working fluid considered for the analysis is water. The fluid flow and heat transfer characteristics of a three-dimensional MCHS are obtained numerically by solving the appropriate governing equations. The flow domain is discretized as finite volume elements and solved using ANSYS CFX 14.5, commercially available CFD code. The numerically predicted results obtained through CFD code are validated with the experiments carried out and it is found that the maximum deviation between the two is less than 5%. Hence the CFD code is further extended to study the influence of geometrical parameters. The channel size optimization has been carried out numerically to obtain the effective heat removal from the MCHS. Average convective heat transfer coefficient, outlet temperature, friction and pressure drop, pumping power and thermal resistance have been plotted against Reynolds number. Non-dimensional parameter, Nusselt number has been plotted as a function of Reynolds number for three heat sinks with different aspect ratios. Friction factor and pressure drop across the channels are obtained and plotted across the channels.