Convective Heat Transfer and Entropy Generation Analysis in Elliptic Microchannels

IF 2.8 4区工程技术 Q2 ENGINEERING, MECHANICAL

Journal of Heat Transfer-transactions of The Asme Pub Date : 2023-11-02 DOI:10.1115/1.4063962

Liangbin Su, Yongyi Yang

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Abstract

Abstract In this paper, we investigate analytically the first and the second law characteristics of fully developed gaseous slip flow with the H1 boundary condition through elliptical microchannels. The closed-form solution of temperature distribution was obtained with the separation of variables method. Expressions for the Nusselt number, the non-dimensional entropy generation rate, and the Bejan number were further deduced. The influences of crucial factors, including viscous dissipation, rarefaction, aspect ratio, and fluid axial heat conduction, have been carefully evaluated. The results indicated that viscous dissipation has a dramatic impact on heat transfer characteristics. But the rarefaction effect was found to significantly reduce the effect of the viscous dissipation on the Nusselt number, and the former may not deteriorate the heat transfer performance when considering the viscous dissipation. The main source of the entropy generation rate is controlled by fluid axial heat conduction when the Peclet number is less than one. The impacts of the viscous dissipation, the rarefaction, and the aspect ratio on entropy generation are magnified when fluid axial conduction dominates the irreversibility. The analytical solutions of the current study will make it possible to compare, evaluate, and optimize alternative elliptical microchannel heat exchanger design options.

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椭圆微通道内对流换热及熵产分析

摘要本文分析研究了带H1边界条件的椭圆微通道内完全发育的气体滑移流动的第一定律和第二定律特性。用分离变量法得到了温度分布的封闭解。进一步推导了Nusselt数、无量纲熵生成率和Bejan数的表达式。对包括粘性耗散、稀薄、展弦比和流体轴向热传导在内的关键因素的影响进行了仔细的评估。结果表明，粘性耗散对换热特性有显著影响。但研究发现，稀薄效应显著降低了粘性耗散对努塞尔数的影响，考虑粘性耗散时，稀薄效应并不会影响换热性能。当Peclet数小于1时，熵产率的主要来源是流体轴向热传导。当流体轴向传导主导不可逆性时，粘性耗散、稀薄和展弦比对熵产的影响被放大。当前研究的分析解决方案将使比较、评估和优化备选椭圆微通道热交换器设计方案成为可能。

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

Journal of Heat Transfer-transactions of The Asme 工程技术-工程：机械

自引率

0.00%

发文量

182

审稿时长

4.7 months

期刊介绍： Topical areas including, but not limited to: Biological heat and mass transfer; Combustion and reactive flows; Conduction; Electronic and photonic cooling; Evaporation, boiling, and condensation; Experimental techniques; Forced convection; Heat exchanger fundamentals; Heat transfer enhancement; Combined heat and mass transfer; Heat transfer in manufacturing; Jets, wakes, and impingement cooling; Melting and solidification; Microscale and nanoscale heat and mass transfer; Natural and mixed convection; Porous media; Radiative heat transfer; Thermal systems; Two-phase flow and heat transfer. Such topical areas may be seen in: Aerospace; The environment; Gas turbines; Biotechnology; Electronic and photonic processes and equipment; Energy systems, Fire and combustion, heat pipes, manufacturing and materials processing, low temperature and arctic region heat transfer; Refrigeration and air conditioning; Homeland security systems; Multi-phase processes; Microscale and nanoscale devices and processes.