Influence of heat flux and Reynolds number on the entropy generation for different types of nanofluids in a hexagon microchannel heat sink

doi:10.1016/j.cjche.2018.08.009

摘要/Abstract

摘要： 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.

关键词: Microchannel heat sink, Nanofluids, Entropy generation, Numerical analysis, Laminar flow

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 words: Microchannel heat sink, Nanofluids, Entropy generation, Numerical analysis, Laminar flow

A.A. Alfaryjat, A. Dobrovicescu, D. Stanciu. Influence of heat flux and Reynolds number on the entropy generation for different types of nanofluids in a hexagon microchannel heat sink[J]. Chinese Journal of Chemical Engineering, 2019, 27(3): 501-513.

参考文献 49

[1]	A. Kosa, Y. Peles, Thermal-hydraulic performance of MEMS-based pin fin heat sink, J. Heat Transf. 128(2006) 121-131.
[2]	Y. Peles, A. Kosar, C. Mishra, C.J. Kuo, B. Schneider, Forced convective heat transfer across a pin fin micro heat sink, Int. J. Heat Mass Transf. 48(2005) 3615-3627.
[3]	H. Shafeie, O. Abouali, K. Jafarpur, G. Ahmadi, Numerical study of heat transfer performance of single-phase heat sinks with micro pin-fin structures, Appl. Therm. Eng. 58(2013) 68-76.
[4]	F.J. Hong, P. Cheng, H. Ge, T.J. Goh, Conjugate heat transfer in tree-shaped microchannel network heat sink for integrated microelectronic cooling application, Int. J. Heat Mass Transf. 50(2007) 4986-4998.
[5]	F. Hong, P. Cheng, Three dimensional numerical analyses and optimization of offset strip-fin microchannel heat sinks, Int. Commun. Heat Mass Transf. 36(2009) 651-656.
[6]	C.A.R. Jimenez, S.G. Kandlikar, A.H. Guerrero, Performance of online and offset micro pin-fin heat sinks with variable fin density, IEEE Trans. Compon. Packag. Manuf. Technol. 3(2013) 86-92.
[7]	B. Shao, L. Wang, H. Cheng, J. Li, Optimization and numerical simulation of multilayer microchannel heat sink, International Conference on Advances in Computational Modeling and Simulation, Procedia Engineering, Vol. 31, 2012, pp. 928-933.
[8]	X. Shanglong, W. Yihao, C. Qiyu, Y. Lili, L. Yue, Optimization of the thermal performance of multi-layer silicon microchannel heat sinks, Therm. Sci. 20(2016) 2001-2013.
[9]	O. Mahian, S. Mahmud, I. Pop, Analysis of first and second laws of thermodynamics between two isothermal cylinders with relative rotation in the presence of MHD flow, Int. J. Heat Mass Transf. 55(2012) 4808-4816.
[10]	A. Bejan, Entropy Generation Minimization, CRC Press, Boca Raton, 1995.
[11]	H. Abbassi, Entropy generation analysis in a uniformly heated microchannel heat sink, Energy 32(2007) 1932-1947.
[12]	G. Ibanez, S. Cuevas, Entropy generation minimization of a MHD (magnetohydrodynamic) flow in a microchannel, Energy 35(2010) 4149-4155.
[13]	M.H. Matin, W.A. Khan, Entropy generation analysis of heat and mass transfer in mixed electrokinetically and pressure driven flow through a slit microchannel, Energy 56(2013) 207-217.
[14]	W.A. Khan, J.R. Culham, M.M. Yovanovich, Optimization of microchannel heat sinks using entropy generation minimization method, IEEE Trans. Compon. Packag. Technol. 32(2009) 243-251.
[15]	M.H. Yazdi, S. Abdullah, I. Hashim, K. Sopian, Reducing entropy generation in MHD fluid flow over open parallel microchannels embedded in a micropatterned permeable surface, Entropy 15(2013) 4822-4843.
[16]	S.U.S. Choi, J. Eastman, Enhancing Thermal Conductivity of Fluids with Nanoparticles, 1995.
[17]	K. Trinavee, T.K. Gogoi, M. Pandey, Laminar convective heat transfer characteristic of Al2O3/water nanofluid in a circular microchannel, J. Phys. Conf. Ser. 759(2016) 012-088.
[18]	A. Ebrahimi, F. Rikhtegar, A. Sabaghan, E. Roohi, Heat transfer and entropy generation in a microchannel with longitudinal vortex generators using nanofluids, Energy 101(2016) 190-201.
[19]	P. Li, Y. Xie, D. Zhang, G. Xie, Heat transfer enhancement and entropy generation of nanofluids laminar convection in microchannels with flow control devices, Entropy 134(2016) 1-15.
[20]	A. Ababaei, M. Abbaszadeh, Second law analyses of forced convection of low-Reynolds-number slip flow of nanofluid inside a microchannel with square impediments, Glob. J. Nanomed. 1(2017).
[21]	T.W. Ting, Y.M. Hung, N. Guo, Entropy generation of nanofluid flow with streamwise conduction in microchannels, Energy 64(2014) 979-990.
[22]	T.W. Ting, Y.M. Hung, N. Guo, Entropy generation of viscous dissipative nanofluid flow in thermal non-equilibrium porous media embedded in microchannels, Int. J. Heat Mass Transf. 81(2015) 862-877.
[23]	T.W. Ting, Y.M. Hung, N. Guo, Viscous dissipation effect on streamwise entropy generation of nanofluid flow in microchannel heat sinks, J. Energy Resour. Technol. ASME 138(2016) 052002-052009.
[24]	Y.T. Yang, Y.H. Wang, B.Y. Huang, Numerical optimization for nanofluid flow in microchannels using entropy generation minimization, Numer. Heat Transf. A 67(2015) 571-588.
[25]	H.H. Najafabadi, M.K. Moraveji, Three-dimensional CFD modeling of fluid flow and heat transfer characteristics of Al2O3/water nanofluid in microchannel heat sink with Eulerian-Eulerian approach, Iran. J. Chem. Eng. 13(2016) 47-61.
[26]	M. Nasiri, M.M. Rashidi, G. Lorenzini, Effect of magnetic field on entropy generation in a microchannel heat sink with offset fan shaped, Entropy 18(2016) 1-12.
[27]	S.S. Khaleduzzaman, M.R. Sohel, I.M. Mahbubul, R. Saidur, J. Selvaraj, Exergy and entropy generation analysis of TiO2-water nanofluid flow through the water block as an electronics device, Int. J. Heat Mass Transf. 101(2016) 104-111.
[28]	J. Li, C. Kleinstreuer, Y. Feng, Computational analysis of thermal performance and entropy generation of nanofluid flow in microchannels, Proceedings of the ASME 3rd Micro/Nanoscale Heat & Mass Transfer International Conference, 2012.
[29]	J. Li, C. Kleinstreuer, Entropy generation analysis for nanofluid flow in microchannels, J. Heat Transf. 132(2010) 122401-122408.
[30]	A.S. Tabrizi, H.R. Seyf, Analysis of entropy generation and convective heat transfer of Al2O3 nanofluid flow in a tangential micro heat sink, Int. J. Heat Mass Transf. 55(2012) 4366-4375.
[31]	M. Hassan, R. Sadri, G. Ahmadi, M.B. Dahari, S.N. Kazi, Numerical study of entropy generation in a flowing nanofluid used in micro-and minichannels, Entropy 15(2013) 144-155.
[32]	S. Heshmatian, M. Bahiraei, Numerical investigation of entropy generation to predict irreversibilities in nanofluid flow within a microchannel:effects of Brownian diffusion, shear rate and viscosity gradient, Chem. Eng. Sci. 172(2017) 52-65.
[33]	P.K. Singh, K.B. Anoop, T. Sundararajan, S.K. Das, Entropy generation due to flow and heat transfer in nanofluids, Int. J. Heat Mass Transf. 53(2010) 4757-4767.
[34]	M.R. Sohel, R. Saidur, N.H. Hassan, M.M. Elias, S.S. Khaleduzzaman, Analysis of entropy generation using nanofluid flow through the circular microchannel and minichannel heat sink, Int. Commun. Heat Mass Transf. 46(2013) 85-91.
[35]	G. Sheikhzadeh, A. Aghaei, H. Ehteram, M. Abbaszadeh, Analytical study of parameters affecting entropy generation of nanofluid turbulent flow in channel and microchannel, Therm. Sci. 20(2016) 2037-2050.
[36]	V. Bianco, S. Nardini, O. Manca, Enhancement of heat transfer and entropy generation analysis of nanofluids turbulent convection flow in square section tubes, Nanoscale Res. Lett. 2(2011) 6-252.
[37]	O. Mahian, A. Kianifar, A.Z. Sahin, S. Wongwises, Heat transfer, pressure drop, and entropy generation in a solar collector using SiO2/water nanofluids:Effects of nanoparticle size and pH, ASME J. Heat Transf. 137(2015) 061011-1-061011-9.
[38]	S.S. Meibodi, A. Kianifar, O. Mahian, S. Wongwises, Second law analysis of a nanofluid-based solar collector using experimental data, J. Therm. Anal. Calorim. 126(2016) 617-625.
[39]	Sh.M. Vanaki, P. Ganesan, H.A. Mohammed, Numerical study of convective heat transfer of nanofluids:A review, Renew. Sust. Energ. Rev. 54(2016) 1212-1239.
[40]	A.A. Alfaryjata, H.A. Mohammedb, N.M. Adamc, D. Stanciua, A. Dobrovicescua, Numerical investigation of heat transfer enhancement using various nanofluids in hexagonal microchannel heat sink, Therm. Sci. Eng. Prog. 5(2018) 252-262.
[41]	R.S. Vajjha, D.K. Das, Experimental determination of thermal conductivity of three nanofluids and development of new correlations, Int. J. Heat Mass Transf. 52(2009) 4675-4682.
[42]	R.S. Vajjha, D.K. Das, D.P. Kulkarni, Development of new correlations for convective heat transfer and friction factor in turbulent regime for nanofluids, Int. J. Heat Mass Transf. 53(2010) 4607-4618.
[43]	M. Corcione, Heat transfer features of buoyancy-driven nanofluids inside rectangular enclosures differentially heated at the sidewalls, Int. J. Therm. Sci. 49(2010) 1536-1546.
[44]	O. Mahian, A. Kianifar, A.Z. Sahin, S. Wongwises, Entropy generation during Al2O3/water nanofluid flow in a solar collector:Effects of tube roughness, nanoparticle size, and different thermophysical models, Int. J. Heat Mass Transf. 78(2014) 64-75.
[45]	Y. Xuan, Q. Li, W. Hu, Aggregation structure and thermal conductivity of nanofluids, AICHE J. 49(2003) 1038-1043.
[46]	J.D. Anderson, Computational Fluid Dynamic:The Basics with Applications, 1995.
[47]	C.J. Ho, L.C. Wei, Z.W. Li, An experimental investigation of forced convective cooling performance of a microchannel heat sink with Al2O3/water nanofluid, Appl. Therm. Eng. 30(2010) 96-103.
[48]	H. Yarmand, G. Ahmadi, S. Gharehkhani, S.N. Kazi, M.R. Safaei, Entropy generation during turbulent flow of zirconia-water and other nanofluids in a square cross section tube with a constant heat flux, Entropy 16(2014) 6116-6132.
[49]	T.P. Teng, Y.H. Hung, T.C. Teng, H.E. Mo, H.G. Hsu, The effect of alumina/water nanofluid particle size on thermal conductivity, Appl. Therm. Eng. 30(2010) 2213-2218.