An exergy and entropy generation investigation in microchannel heat sink utilizing alumina nanofluid at varied concentrations with conjugate heat transfer

IF 3 3区 工程技术 Q2 CHEMISTRY, ANALYTICAL
Sandeep Gupta, P. M. V. Subbarao
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Abstract

This research presents an experimental assessment of exergy and entropy generation in a straight circular multi-microchannel stainless steel heatsink. Deionized water and water/alumina nanofluids with 1–4% (m/m) concentrations are used as cooling fluids in the heat sink, operating at low Reynolds numbers (10 ≤ Re ≤ 50). The primary goals of the exergy analysis are to evaluate the first and second laws of thermodynamics, including exergy output, gain, and loss. Entropy generation analysis encompasses both heat transfer and flow entropy. The study’s main innovation is the examination of exergy and entropy generation in microchannel heat sinks using nanofluids at low Reynolds numbers. The results show that nanofluids with a 4% nanoparticle concentration achieve a higher exergy gain of 56% compared to DI water at Re = 40. Exergy loss increases with Reynolds numbers and with increase in the nanoparticles concentration up to 4%, the exergy loss increases up to 27% at Re = 10. Back conduction, significant at low Reynolds numbers, does not affect the second law efficiency. The highest second law efficiency occurs at Re = 10, with DI water achieving 7.2% under high heat flux, while nanofluids with 4% nanoparticle concentration show 5.9%. This efficiency decreases with Reynolds number and nanoparticle concentrations. However, introducing alumina nanoparticles into DI water reduces entropy generation; at Re = 50, the total entropy generation is 0.0013 W K−1 for DI water and 0.001 W K−1 for nanofluids with a 4% nanoparticle concentration. Nanofluids reduce entropy generation up to 27% at a 4% concentration of nanoparticles compared to DI water at Re = 40. These findings offer valuable insights for optimizing the design and performance of microchannel heat sink configurations for various thermal management applications, focusing on exergy and entropy generation.

Abstract Image

利用不同浓度氧化铝纳米流体与共轭传热的微通道散热器的能耗和熵生成研究
本研究通过实验评估了直圆形多微通道不锈钢散热器中产生的放能和熵。散热器中使用浓度为 1-4% (m/m) 的去离子水和水/氧化铝纳米流体作为冷却流体,在低雷诺数(10 ≤ Re ≤ 50)下运行。放能分析的主要目的是评估热力学第一和第二定律,包括放能输出、增益和损失。熵产生分析包括热传递和流动熵。该研究的主要创新点是在低雷诺数条件下,对使用纳米流体的微通道散热器的放能和熵生成进行研究。结果表明,在 Re = 40 条件下,纳米颗粒浓度为 4% 的纳米流体比去离子水的放能增益高 56%。放热损失随雷诺数增加而增加,随着纳米粒子浓度增加到 4%,在 Re = 10 时放热损失增加到 27%。反向传导在低雷诺数时非常明显,但并不影响第二定律效率。最高的第二定律效率出现在 Re = 10 时,去离子水在高热流量下的效率为 7.2%,而纳米粒子浓度为 4% 的纳米流体的效率为 5.9%。该效率随雷诺数和纳米粒子浓度的增加而降低。然而,在去离子水中引入氧化铝纳米粒子可减少熵的产生;在 Re = 50 时,去离子水的总熵产生量为 0.0013 W K-1,而纳米粒子浓度为 4% 的纳米流体的总熵产生量为 0.001 W K-1。在 Re = 40 条件下,与去离子水相比,纳米粒子浓度为 4% 的纳米流体最多可减少 27% 的熵产生。这些发现为优化各种热管理应用的微通道散热器配置的设计和性能提供了有价值的见解,重点是能量和熵的产生。
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来源期刊
CiteScore
8.50
自引率
9.10%
发文量
577
审稿时长
3.8 months
期刊介绍: Journal of Thermal Analysis and Calorimetry is a fully peer reviewed journal publishing high quality papers covering all aspects of thermal analysis, calorimetry, and experimental thermodynamics. The journal publishes regular and special issues in twelve issues every year. The following types of papers are published: Original Research Papers, Short Communications, Reviews, Modern Instruments, Events and Book reviews. The subjects covered are: thermogravimetry, derivative thermogravimetry, differential thermal analysis, thermodilatometry, differential scanning calorimetry of all types, non-scanning calorimetry of all types, thermometry, evolved gas analysis, thermomechanical analysis, emanation thermal analysis, thermal conductivity, multiple techniques, and miscellaneous thermal methods (including the combination of the thermal method with various instrumental techniques), theory and instrumentation for thermal analysis and calorimetry.
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