Three‐dimensional computational comparison of mini pinned heat sinks using different nanofluids: Part one—the hydraulic‐thermal characteristics

Abstract

The hydraulic-thermal characteristics of 3D pinned heat sink designs have been numerically compared as the first part of a three-part investigation. Five different pin geometries (circular, square, triangular, strip, and elliptic pins) and an unpinned heat sink with three types of nanofluids (Al 2 O 3 -H 2 O, SiO 2 -H 2 O, and CuO-H 2 O) are considered for laminar forced convection. The range of Reynolds number is from 100 to 1000, and volume fractions vary between 0% and 5%.The finite volume method is employed to solve the Navier-Stokes and energy equations by employing a SIMPLE algorithm for a computational solution. Three parameters are presented-the Nusselt number, the bottom temperature, and the hydrothermal performance of the heat sink with pressure drop data. The findings indicated that the overall hydrothermal performance of elliptic-pinned (EP) heat sinks produces the most substantial value of 3.10 for pure water. For different nanofluids, the SiO 2 -water nanofluids with EPs have the most significant hydrothermal performance. Also, this factor is enhanced with an increase in nanofluid concentration up to nearly 3.34 for 5% of SiO 2 -water. Consequently, applying the elliptic-pinned heat sinks is recommended with pure water for considering an increase in the pressure drop, with 5% of SiO 2 -water nanofluids, regardless of an enlargement of pressure drop for heat-dissipation applications. K E Y W O R D Scooling rate enhancements, hydrothermal performance augmentation, pinned heat sinks, using different nanofluids 1 | INTRODUCTION Many cooling techniques have been suggested for improving the hydraulic-thermal performance of macro, mini, and micro heat sinks to overcome the main challenge of electronic cooling systems with a high density of heat generation. The improvement in the hydraulic thermal design of heat sink leads to a reduction in its size and weight and enhances the cooling rate; thereby, avoiding failure and increasing the reliability and speed performance of engineering devices. 1 Therefore, pinned heat sinks are one of the most common techniques used to improve the thermo-hydraulic performance of heat sinks because heat sinks with pins are applied in the liquid and gas processes of many engineering applications. Pinned heat sinks are proposed as a cooling technique with water and nanofluids to enhance the cooling performance of heat sinks. 1-3 Thus, many researchers have investigated different kinds of heat sinks with various fluid types to overcome the issue of rapidly developing heat generated in electronic systems and their applications for protecting these systems from damage.Many numerical studies on heat sinks with pins using liquid cooling have been performed. For example, Ambreen et al 4 reported the hydrothermal characteristics of circular micro-pinned heat sinks with Al 2 O 3 -H 2 O nanofluids (0.25%-1%) using the Lagrangian-Eulerian approach. The results showed that the hydrothermal performance was enhanced upon using nanofluids with an increase in volume fraction instead of pure wa...

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