Study of hydrothermal transport phenomena and performance characteristics for a flow through a diamond (diverging-converging) microchannel

A three-dimensional computational module is undertaken to assimilate the hydrothermal transport phenomena and performance characteristics of a single-phase laminar flow through a diamond (diverging-converging) microchannel. The fluid flow and heat transfer characteristics are investigated as a function of divergence-convergence angle, width ratio (ratio of bigger width to smaller width), and Reynolds number. The results are explained with the help of velocity and temperature profiles. The present study also utilizes thermal enhancement factor, pressure penalty factor, performance evaluation index, frictional and thermal entropy generation, Bejan number, and augmented entropy generation number to analyze the hydrothermal and thermodynamic performance characteristics of a diamond microchannel. The Nusselt number is found to be a direct function of the divergence-convergence angle, while it varies inversely with the width ratio. The varying divergence-convergence angle effectively constrains the rise in the overall temperature gradient, while the width ratio has a weak but opposite effect on the temperature gradients. The results also indicate that the diamond microchannel exhibits better hydrothermal and thermodynamic performance than the uniform microchannel. For a given range of parameters, the maximum value of the performance evaluation index is 1.42, and the maximum reduction in entropy generation is 28% relative to a uniform microchannel. These results would serve as a valuable guide for designing and optimizing microchannels with diverging-converging profiles required in several heat transfer applications.