Thermodynamic analysis and optimization of fully developed turbulent forced convection in a circular tube with water-Al2O3 nanofluid

Abstract In this paper, results of a thermodynamic investigation using the entropy generation minimization method for fully developed turbulent forced convection in a circular tube using water–Al 2 O 3 nanofluid are presented. Circular tube cross section areas in the range 0.0000025 ⩽  A c  ⩽ 0.05 m 2 were considered. Nanofluid volume fractions in the range 0% ⩽  ϕ  ⩽ 6% and Reynolds numbers in the range 5000 ⩽  Re  ⩽ 180,000 were used for each of the circular tube cross section areas considered. The entropy generation rates were determined numerically from the temperature and velocity fields obtained during the computational fluid dynamics analysis. From the study, it is shown that there is an optimal cross section area at each Reynolds number for which the entropy generation in the tube is a minimum. The optimal cross section area increases as the Reynolds number increases. The study also shows presence of a Reynolds number at each nanofluid volume fraction and cross section area beyond which using nanofluids does not make thermodynamic sense. Correlations for the optimal Reynolds number and Reynolds number beyond which using nanofluids makes no thermodynamics sense were derived and presented.

[1]  Rahman Saidur,et al.  Heat transfer and entropy analysis of three different types of heat exchangers operated with nanofluids , 2012 .

[2]  T. Mahlia,et al.  Entropy generation analysis of nanofluid flow in a circular tube subjected to constant wall temperature , 2012 .

[3]  A. Bejan.  Fundamentals of exergy analysis, entropy generation minimization, and the generation of flow architecture , 2002 .

[4]  Josua P. Meyer,et al.  Thermodynamic optimisation and computational analysis of irreversibilities in a small-scale wood-fired circulating fluidised bed adiabatic combustor , 2014 .

[5]  N. Galanis,et al.  Heat transfer enhancement by using nanofluids in forced convection flows , 2005 .

[6]  J. Eastman,et al.  Measuring Thermal Conductivity of Fluids Containing Oxide Nanoparticles , 1999 .

[7]  Patricia E. Gharagozloo,et al.  A Benchmark Study on the Thermal Conductivity of Nanofluids , 2009 .

[8]  H. Herwig,et al.  Entropy production calculation for turbulent shear flows and their implementation in cfd codes , 2005 .

[9]  K. Ting,et al.  Entropy generation and optimal analysis for laminar forced convection in curved rectangular ducts : A numerical study , 2006 .

[10]  A. K. Satapathy,et al.  Thermodynamic optimization of a coiled tube heat exchanger under constant wall heat flux condition , 2009 .

[11]  Soteris A. Kalogirou,et al.  Solar thermal collectors and applications , 2004 .

[12]  A. Bejan.  Entropy Generation Minimization: The Method of Thermodynamic Optimization of Finite-Size Systems and Finite-Time Processes , 1995 .

[13]  Davood Domiri Ganji,et al.  An analytical study on entropy generation of nanofluids over a flat plate , 2013 .

[14]  A. Bejan.  A Study of Entropy Generation in Fundamental Convective Heat Transfer , 1979 .

[15]  Josua P. Meyer,et al.  Numerical investigation of entropy generation in a parabolic trough receiver at different concentration ratios , 2013 .

[16]  Wenhua Yu,et al.  Nanofluids: Science and Technology , 2007 .

[17]  T. Ko,et al.  Numerical investigation on developing laminar forced convection and entropy generation in a wavy channel , 2007 .

[18]  D. Cahill,et al.  Nanofluids for thermal transport , 2005 .

[19]  T. H. Ko.  Numerical investigation on laminar forced convection and entropy generation in a curved rectangular duct with longitudinal ribs mounted on heated wall , 2006 .

[20]  G. Batchelor.  The effect of Brownian motion on the bulk stress in a suspension of spherical particles , 1977, Journal of Fluid Mechanics.

[21]  H. Seyf,et al.  Analysis of entropy generation and convective heat transfer of Al2O3 nanofluid flow in a tangential micro heat sink , 2012 .

[22]  T. H. Ko,et al.  A numerical study on entropy generation induced by turbulent forced convection in curved rectangular ducts with various aspect ratios , 2009 .

[23]  Vincenzo Bianco,et al.  Numerical investigation on nanofluids turbulent convection heat transfer inside a circular tube , 2011 .

[24]  A. Mujumdar,et al.  Heat transfer characteristics of nanofluids: a review , 2007 .

[25]  Xianfan Xu,et al.  Thermal Conductivity of Nanoparticle -Fluid Mixture , 1999 .

[26]  Xiao Dong Chen,et al.  Entropy production during the drying process of milk droplets in an industrial spray dryer , 2011 .

[27]  H. Blasius,et al.  Das Aehnlichkeitsgesetz bei Reibungsvorgängen in Flüssigkeiten , 1913 .

[28]  H. Herwig,et al.  Direct and indirect methods of calculating entropy generation rates in turbulent convective heat transfer problems , 2006 .

[29]  O. Manca,et al.  Numerical study of a confined slot impinging jet with nanofluids , 2011, Nanoscale research letters.

[30]  D. Spalding,et al.  A calculation procedure for heat, mass and momentum transfer in three-dimensional parabolic flows , 1972 .

[31]  Somchai Wongwises,et al.  Enhancement of heat transfer using nanofluids—An overview , 2010 .

[32]  Vincenzo Bianco,et al.  Performance analysis of turbulent convection heat transfer of Al2O3 water-nanofluid in circular tubes at constant wall temperature , 2014 .

[33]  C. T. Nguyen,et al.  Numerical investigation of laminar flow and heat transfer in a radial flow cooling system with the use of nanofluids , 2004 .

[34]  H. Herwig,et al.  Local entropy production in turbulent shear flows: a high-Reynolds number model with wall functions , 2004 .

[35]  S. Russeil,et al.  Numerical investigation of local entropy production rate of a finned oval tube with vortex generators , 2009 .

[36]  D. A. G. Bruggeman.  Berechnung verschiedener physikalischer Konstanten von heterogenen Substanzen. I. Dielektrizitätskonstanten und Leitfähigkeiten der Mischkörper aus isotropen Substanzen , 1935 .

[37]  Jiangfeng Guo,et al.  The effect of temperature-dependent viscosity on entropy generation in curved square microchannel , 2012 .

[38]  T. Ko.  A numerical study on developing laminar forced convection and entropy generation in half-and double-sine ducts , 2007 .

[39]  Ching-Jenq Ho,et al.  Numerical simulation of natural convection of nanofluid in a square enclosure: Effects due to uncertainties of viscosity and thermal conductivity , 2008 .

[40]  Thirumalachari Sundararajan,et al.  Entropy generation due to flow and heat transfer in nanofluids , 2010 .

[41]  Vincenzo Bianco,et al.  Entropy generation analysis of turbulent convection flow of Al2O3–water nanofluid in a circular tube subjected to constant wall heat flux , 2014 .

[42]  N. Fuchikami,et al.  Thermodynamics of computing: Entropy of nonergodic systems. , 2001, Chaos.

[43]  T. Shih,et al.  A new k-ϵ eddy viscosity model for high reynolds number turbulent flows , 1995 .

[44]  J. Meyer,et al.  Heat transfer and thermodynamic performance of a parabolic trough receiver with centrally placed perforated plate inserts , 2014 .

[45]  Saeed Zeinali Heris,et al.  Analysis of entropy generation between co-rotating cylinders using nanofluids , 2012 .

[46]  H. Brinkman.  The Viscosity of Concentrated Suspensions and Solutions , 1952 .

[47]  Di Zhang,et al.  Heat transfer and flow analysis of Al2O3–water nanofluids in microchannel with dimple and protrusion , 2014 .

[48]  Mourad Bouterra,et al.  Heat transfer and entropy generation analysis of nanofluids flow in an open cavity , 2013 .

[49]  Chris Aldrich,et al.  The cross-entropy method in multi-objective optimisation: An assessment , 2011, Eur. J. Oper. Res..

[50]  Y. Çengel.  Heat and Mass Transfer: Fundamentals and Applications , 2000 .