A flow structure design based novel micro heatsink

Abstract

In the modern world, recent technological advancement in various fields of science leads to the emergence of very tiny electronic devices, which require highly efficient cooling for prolonged functioning. Thus, designing a novel micro heatsink with a cutting-edge geometric configuration, which can cool these sophisticated devices at lower pressure drop, is most desirable. A three-dimensional numerical study of conjugate heat transfer has been carried out to propose a micro heatsink design having disruptive structures placed in a regular and staggered pattern along the length of the rectangular microchannel about the longitudinal vertical midplane. Heatsinks are made of silicon with rectangular channels, and disruptive structures like microchambers, secondary branches, and blockages engraved in them. The effectiveness of these disruptive structures is analyzed using performance parameters like heat transfer, friction factor, thermal performance (TP), and entropy generation (EG) due to heat transfer, entropy generation due to pressure drop, and entropy generation number (EGN) over a Reynolds number (Re) ranging from 65 to 530. Deionized water is used as a working fluid. A heatsink design having the highest TP and minimum EGN has been identified from the rigorous analysis among the microchannels of aligned microchamber, oblique microchamber, secondary branch and blockage, and oblique microchamber with secondary branch and blockage (OMSBB). The best configuration has been determined based on the highest TP, i.e., highest heat transfer with the same pumping power and lowest EGN, i.e., minimum heatsink temperature. OMSBB is found to be the best among all the channels. Later, the parametric variation of the angle of the secondary branch, position of the secondary branch, length of the microchamber, and pitch distance has been done to find the best combination of geometrical dimensions having maximum TP and minimum EGN. The values have been obtained equal to 1.71 and 0.55, respectively, at Re of 397. The significant roles of the longitudinal and transverse vortex, recirculation, and area of heat transfer on the augmentation of heat transfer and minimizations of EG mechanism with the alteration of geometrical parameters are exploited and described explicitly. Finally, correlations have been established meticulously based on response surface methodology between heat transfer enhancement and rise in pressure drop dependence on geometric parameters.