An exergy and entropy generation investigation in microchannel heat sink utilizing alumina nanofluid at varied concentrations with conjugate heat transfer
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引用次数: 0
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.
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.