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Influence of heat flux and Reynolds number on the entropy generation for different types of nanofluids in a hexagon microchannel heat sink
Influence of heat flux and Reynolds number on the entropy generation for different types of nanofluids in a hexagon microchannel heat sink
A.A. Alfaryjat, A. Dobrovicescu, D. Stanciu
Faculty of Mechanical Engineering and Mechatronics, University Politehnica of Bucharest, Splaiul Independentei nr. 313, sector 6, Bucuresti, Romania

Influence of heat flux and Reynolds number on the entropy generation for different types of nanofluids in a hexagon microchannel heat sink
A.A. Alfaryjat, A. Dobrovicescu, D. Stanciu
Faculty of Mechanical Engineering and Mechatronics, University Politehnica of Bucharest, Splaiul Independentei nr. 313, sector 6, Bucuresti, Romania


Abstract: Based on the Second Law of Thermodynamics, the entropy generation is studied for laminar forced convection flow of different nanoparticles (Al2O3, CuO and SiO2) mixed with water through a hexagon microchannel heat sink (HMCHS). The effects of different heat fluxes and Reynolds numbers on the entropy generation for different nanofluids, volume fractions and nanoparticles diameter are investigated. The heat flux is in the range of 125 to 500 kW·m-2 and the Reynolds numbers vary between 200 and 1500. The thermal, frictional and total entropy generations are calculated by integrating the volumetric rate components over the entire HMCHS. The results clearly show that the rise in the heat flux leads to an increase in the thermal entropy generation for nanofluids and pure water but they don't have any influence on the frictional entropy generation. Moreover, when the Reynolds number increases, the frictional entropy generation increases while the thermal entropy generation decreases. The results revealed that at low heat fluxes and high Reynolds numbers, pure water gives the lowest entropy generation, while at high heat flux the nanofluid has to be used in order to lower the overall irreversibility.
Key wordsMicrochannel heat sink   Nanofluids   Entropy generation   Numerical analysis   Laminar flow  
收稿日期: 2018-04-11; 出版日期: 2018-08-19
链接本文:  
http://www.cjche.com.cn/CN/10.1016/j.cjche.2018.08.009        http://www.cjche.com.cn/CN/Y2019/V27/I3/501