Investigation of entropy generation analysis of Gallium alloy based nanofluids in minichannel heat sink

This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

In the present study, entropy generation analysis is numerically performed for single-phase laminar flow inside a 3-D minichannel heat sink at Reynolds numbers Re = 300–1900. The influence of different cooling fluids water, GaIn, GaIn nanofluids (GaIn-6 %Alumina, GaIn-6 %CNT, GaIn-6 %Diamond) and substrates (Si silicon, AlN aluminum nitride, Cu copper alloy) on the entropy generation is investigated for a uniform heat flux in a minichannel (M/C). Among GaIn-based nanofluids (N/Fs), GaIn, and water, it is found that GaIn-6 %CNT has the lowest value of total entropy generation per unit length (Sgen,tot) for Cu, AlN, and Si substrates. Besides, when GaIn-6 %CNT serves as a coolant, Si-based M/C offers the highest Sgen,tot = 0.475 Wm-1K−1, at Re = 300, whereas Cu-based M/C has the lowest Sgen,tot = 0.25 Wm-1K−1, at Re = 1900. Among all the materials, Cu has the lowest Sgen,tot, followed by AlN and Si, at all the values of Re for GaIn N/Fs. Besides, the study explores the variation of the Ga alloy nanofluids (GaIn-CNT, GaSn-CNT, EGaIn-CNT, EGaInSn-CNT), volume fractions (φ = 0–10 %), Reynolds numbers (300–1900), and heat fluxes (qb = 100–900 Wcm−2), on the frictional, thermal, total entropy generation, and Bejan number inside the 3-D minichannel. Among Ga alloy nanofluids, it is found that GaInSn-6 %CNT shows the highest total entropy generation, and GaIn-6 %CNT has the lowest Sgen,tot at Re = 300–1900 for qb = 100 Wcm−2. Also, it is observed that the minimum value of Sgen,tot is noted for GaIn-CNT, followed by GaSn-CNT, EGaIn-CNT, and EGaInSn-CNT at all values of concentrations, Re, and AlN substrate.