Efficient microsink design to maximize the thermal performance

The indigenous design of the microsink with its geometric structures provides efficient cooling at minimal pressure drop for small electronic devices. A comprehensive three-dimensional numerical analysis of conjugate heat transfer has been carried out with the disruptive structures in a rectangular microchannel to propose a microsink. The rectangular microchannel has been designed with fan-shaped cavities (FC), secondary branches (SB), and blockage (B) and uses water as a working fluid. The effects of these structures are analyzed on the basis of heat transfer, friction factor, and thermal performance (TP) for the Reynolds number (Re) in the range of 141 to 596. The best microchannel has been recognized from the detailed investigation of channels with only fan-shaped cavities (FC), fan-shaped cavities with secondary branches (FCSB), and fan-shaped cavities with secondary branches and blockage (FCSBB) on the basis of highest TP. The channel FCSBB attains the highest thermal performance compared to the other two channels. Systematic variations of geometrical parameters have been carried out, such as width (W sb ) and angle (θ) of secondary branches, the length (L fc ) and width (W fc ) of the cavities, and pitch distance (B) to achieve the highest TP. The systematic study of parametric variations of FCSBB attains the highest TP value of 2.04 at Re equal to 395.65. The optimal combination of relative parameters determined as relative width of secondary branches (δ), relative angle of secondary branches (φ), relative length of cavities (β), relative width of cavities (α) and relative pitch distance (λ) are 0.01, 0.50, 0.060, 1.0, and 0.133 respectively. The substantial contribution of the longitudinal vortices to the enhancement of heat transfer with the variation of geometrical aspects is investigated and discussed in detail. The distribution of wall shear stress along the length of cavities describes the recirculation zones of fluid inside the fan-shaped cavities. Also, the relation of shear stress with increase in heat transfer and the pressure drop is established.