Three-Dimensional Numerical Study of Conjugate Heat Transfer in Diverging Microchannel

摘要

Increase in applications of varying cross sectional area microchannels in microdevices has provided the need to understandudfluid flow and heat transfer through such flow passages. This study focuses on conjugate heat transfer study through auddiverging microchannel. Three-dimensional numerical simulations are performed using commercially available package.udDiverging microchannels with different geometrical configurations (i.e. varying angle: 1-8°, depth: 86-200 μm, solid-to-udfluid thickness ratio: 1.5-4) are employed for this purpose. Simulations are carried out for varying mass flow rate (3.3 xud10ud–5ud-8.3 x 10ud–5ud kg/s) and heat flux (2.4-9.6 W/cmud2ud) conditions. Heat distribution along the flow direction is studied toudunderstand the effect of wall conduction. Wall conduction number (udMud) varies from 0.006 to 0.024 for the range ofudparameters selected in the study. Wall conduction is observed to be a direct function of depth and solid-to-fluid thicknessudratio, and varies inversely with angle of diverging microchannel. It is observed that the area variation and wall conductionudcontribute separately towards redistribution of the supplied heat flux. This leads to reduced temperature gradients inuddiverging microchannel. The results presented in this work will be useful for designing future microdevices involving heating or cooling