Comparative analysis of microchannel heat sinks for different values of the Prandtl and Reynolds numbers

IF 4 3区 工程技术 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS
Evans Joel Udom, Marcello Lappa
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Abstract

Purpose

This study aims to perform a comprehensive comparative analysis of the performance of microchannel heat sinks (MCHS) across a wide range of operating conditions. It investigates the interplay between heat transfer efficiency, frictional effects and flow dynamics in different channel configurations and fluid types.

Design/methodology/approach

The analysis is conducted through numerical simulations, solving the governing equations for mass, momentum and energy conservation. Multiple channel geometries are evaluated, each incorporating specific strategies to disrupt the thermal boundary layer along the heated channel surface. The study also considers the influence of transverse vorticity effects arising from abrupt or smooth geometric variations. The performance is assessed for three distinct fluids – mercury, helium and water – to examine the complex interplay between fluid properties (e.g. viscosity and thermal diffusivity), momentum losses and heat transfer gains. Key parameters, including the Reynolds number and Prandtl number, are systematically varied to uncover their impact on heat transfer coefficients, vorticity distribution and flow stability.

Findings

The study reveals that microchannels with wavy geometries and double internal bifurcations consistently deliver superior thermal performance compared to other configurations, regardless of the working fluid. The results highlight that variations in the Prandtl number significantly influence the dimensional convective heat transfer coefficient, vorticity patterns and the onset of fluid-dynamic instabilities for a fixed Reynolds number and geometry. The authors introduce a correlation for the Nusselt number with the exponents for the Reynolds and Prandtl numbers being ½ and ¼, respectively; the authors also show that, in agreement with existing literature, the friction factor is primarily affected by the Reynolds number and channel shape, demonstrating no dependence on the Prandtl number.

Originality/value

This research provides novel insights into the non-linear scaling of heat transfer and momentum loss with fluid properties in MCHS. The systematic exploration of fluid and geometric interactions enriches the current understanding of microchannel heat transfer mechanisms, presenting actionable recommendations for real-world applications.

不同普朗特数和雷诺数下微通道散热器的比较分析
本研究旨在对微通道散热器(MCHS)在各种工况下的性能进行全面的比较分析。研究了不同通道构型和流体类型下的换热效率、摩擦效应和流动动力学之间的相互作用。设计/方法/途径通过数值模拟,求解质量、动量和能量守恒的控制方程进行分析。评估了多个通道几何形状,每个通道都包含特定的策略来破坏沿着加热通道表面的热边界层。研究还考虑了横向涡度效应对突变或平滑几何变化的影响。对三种不同的流体(汞、氦和水)的性能进行了评估,以检查流体性质(例如粘度和热扩散率)、动量损失和传热增益之间复杂的相互作用。系统地改变了包括雷诺数和普朗特数在内的关键参数,以揭示它们对传热系数、涡度分布和流动稳定性的影响。研究结果表明,与其他配置相比,具有波浪几何形状和双内部分岔的微通道始终具有优越的热性能,无论工作流体如何。结果表明,在固定雷诺数和几何形状下,普朗特数的变化显著影响了尺度对流换热系数、涡度模式和流体动力不稳定性的发生。作者介绍了努塞尔数与雷诺数和普朗特数的指数分别为1 / 2和1 / 4的相关性;作者还表明,与现有文献一致,摩擦系数主要受雷诺数和通道形状的影响,而与普朗特数无关。独创性/价值本研究为MCHS中流体性质的传热和动量损失的非线性标度提供了新的见解。流体和几何相互作用的系统探索丰富了当前对微通道传热机制的理解,为现实世界的应用提出了可行的建议。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
CiteScore
9.50
自引率
11.90%
发文量
100
审稿时长
6-12 weeks
期刊介绍: The main objective of this international journal is to provide applied mathematicians, engineers and scientists engaged in computer-aided design and research in computational heat transfer and fluid dynamics, whether in academic institutions of industry, with timely and accessible information on the development, refinement and application of computer-based numerical techniques for solving problems in heat and fluid flow. - See more at: http://emeraldgrouppublishing.com/products/journals/journals.htm?id=hff#sthash.Kf80GRt8.dpuf
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