Abstract
A novel microchannel heat sink with oval-shaped micro pin fins (MOPF) is proposed and the characteristics of fluid flow and heat transfer are studied numerically for Reynolds number (Re) ranging from 157 to 668. In order to study the influence of geometry on flow and heat transfer characteristics, three non-dimensional variables are defined, such as the fin axial length ratio (α), width ratio (β), and height ratio (γ). The thermal enhancement factor (η) is adopted as an evaluation criterion to evaluate the best comprehensive thermal-hydraulic performance of MOPF. Results indicate that the oval-shaped pin fins in the microchannel can effectively prevent the rise of heat surface temperature along the flow direction, which improves the temperature distribution uniformity. In addition, results show that for the studied Reynolds number range and microchannel geometries in this paper, the thermal enhancement factor η increases firstly and then decreases with the increase of α and β. In addition, except for Re = 157, η decreases first and then increases with the increase of the fin height ratio γ. The thermal enhancement factor for MOPF with α = 4, β = 0.3, and γ = 0.5 achieves 1.56 at Re = 668. The results can provide a theoretical basis for the design of a microchannel heat exchanger.
Highlights
In this study, oval-shaped micro pin fins are arranged in a smooth rectangular channel as a new finned microchannel, and the heat and heat transfer performance are investigated by numerical methods
It suggests that the enhanced heat transfer of the microchannel with micro pin fins is primarily attributed to flow separation, disturbance effect, and the vortexes in the mainstream rather than surface area enlargement
The oval-shaped micro pin fins are helpful to heat transfer enhancement due to flow separation, disturbance effect, and the vortexes in the mainstream
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. With the increasing advanced technology in energy, electronics, aerospace, medicine, chemical industry, and other fields, the corresponding equipment gradually develop in the direction of high-power, high performance, and miniaturization, such as large solid laser array, high-power LED lighting equipment, high integration microelectronics devices, etc These electronic devices usually have a small heat transfer surface but a high-heat flux rate [1,2]. A microchannel combined with cone-shaped micro pin fins (MCPF) was proposed, and the heat transfer and fluid flow characteristics of MCPF were numerically investigated. In this study, oval-shaped micro pin fins are arranged in a smooth rectangular channel as a new finned microchannel, and the heat and heat transfer performance are investigated by numerical methods. The influence of fin axial length ratio (α), fin width ratio (β), and fin height ratio (γ) on the flow and heat transfer performance is investigated, and the thermal enhancement factor is used to evaluate the overall performance of MOPF
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