CFD study of heat transfer and fluid flow in a parabolic trough solar receiver with internal annular porous structure and synthetic oil–Al2O3 nanofluid

Abstract In this study, a finite volume method is employed to investigate the performance of a novel parabolic trough solar collector with synthetic oil–Al2O3 nanofluid as the heat transfer fluid. An annular porous structure is installed inside the absorber tube to improve heat transfer. The effects of the simultaneous utilization of porous structure and nanoparticle addition on heat transfer, pressure drop, and thermal efficiency of the receiver are investigated for different values of Reynolds number, volume fraction of nanoparticle, inlet temperature and Darcy number of the porous region. The results show that as Reynolds number and volume fraction of nanoparticle increase, heat transfer coefficient, pressure drop, and thermal efficiency increase. However, the increases in inlet temperature lead to the decreases in heat transfer coefficient, pressure drop, and thermal efficiency. At Reynolds numbers higher than 30 × 10 4 , simultaneous utilization of porous structure with Da = 0.3 and nanoparticles increases heat transfer coefficients nearly 7% and 20%, pressure drops up to 42.5% and 42%, thermal efficiencies up to 8% and 15%, overall efficiencies nearly 5% and 14%, and exergetic efficiencies by 7% and 15% for inlet temperature of 500 and 600 K, respectively.

[1]  Sheng‐Qi Zhou,et al.  Measurement of the specific heat capacity of water-based Al2O3 nanofluid , 2008 .

[2]  H. Oztop,et al.  Numerical study of natural convection in partially heated rectangular enclosures filled with nanofluids , 2008 .

[3]  Evangelos Bellos,et al.  Optimum number of internal fins in parabolic trough collectors , 2018, Applied Thermal Engineering.

[4]  Ali J. Chamkha,et al.  Conjugate heat transfer and entropy generation in a cavity filled with a nanofluid-saturated porous media and heated by a triangular solid , 2016 .

[5]  Robert A. Taylor,et al.  Recent advances in modeling and simulation of nanofluid flows-Part I: Fundamentals and theory , 2019, Physics Reports.

[6]  S. Patankar.  Numerical Heat Transfer and Fluid Flow , 2018, Lecture Notes in Mechanical Engineering.

[7]  Josua P. Meyer,et al.  Optimal thermal and thermodynamic performance of a solar parabolic trough receiver with different nanofluids and at different concentration ratios , 2017 .

[8]  Ioan Pop,et al.  A heatline analysis of natural convection in a square inclined enclosure filled with a CuO nanofluid under non-uniform wall heating condition , 2012 .

[9]  Majid Siavashi,et al.  Numerical investigation of flow characteristics, heat transfer and entropy generation of nanofluid flow inside an annular pipe partially or completely filled with porous media using two-phase mixture model , 2015 .

[10]  K. Goudarzi,et al.  An experimental investigation on the simultaneous effect of CuO–H2O nanofluid and receiver helical pipe on the thermal efficiency of a cylindrical solar collector , 2014 .

[11]  Morimoto Yasuo,et al.  Forced convective heat transfer in uniformly heated horizontal tubes 1st report—Experimental study on the effect of buoyancy , 1966 .

[12]  Somchai Wongwises,et al.  Entropy generation during Al2O3/water nanofluid flow in a solar collector: Effects of tube roughness, nanoparticle size, and different thermophysical models , 2014 .

[13]  M. Siavashi,et al.  Two-phase mixed convection heat transfer and entropy generation analysis of a non-Newtonian nanofluid inside a cavity with internal rotating heater and cooler , 2019, International Journal of Mechanical Sciences.

[14]  E. Bellos,et al.  Alternative designs of parabolic trough solar collectors , 2019, Progress in Energy and Combustion Science.

[15]  S. Wongwises,et al.  An experimental study on the heat transfer performance and pressure drop of TiO2-water nanofluids flowing under a turbulent flow regime , 2010 .

[16]  S. Kalogirou.  Solar Energy Engineering: Processes and Systems , 2009 .

[17]  A. Ranjbar,et al.  Numerical Study On Thermal Performance Of Solar Parabolic Trough Collector , 2013 .

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

[19]  Ali J. Chamkha,et al.  Mixed convection in a square cavity filled with CuO-water nanofluid heated by corner heater , 2017 .

[20]  Aldo Steinfeld,et al.  Potential improvements in the optical and thermal efficiencies of parabolic trough concentrators , 2014 .

[21]  M. Ismael,et al.  Natural Convection Heat Transfer in Arc Shape Wall Porous Cavity Filled with Nano-Fluid , 2014 .

[22]  A. Ede.  The heat transfer coefficient for flow in a pipe , 1961 .

[23]  I. Pop,et al.  A review of the applications of nanofluids in solar energy , 2013 .

[24]  W. Swinbank.  Long‐wave radiation from clear skies , 1963 .

[25]  Josua P. Meyer,et al.  Thermal performance and entropy generation analysis of a high concentration ratio parabolic trough solar collector with Cu-Therminol®VP-1 nanofluid , 2016 .

[26]  U. C. Arunachala,et al.  Solar parabolic trough collectors: A review on heat transfer augmentation techniques , 2017 .

[27]  Young I Cho,et al.  HYDRODYNAMIC AND HEAT TRANSFER STUDY OF DISPERSED FLUIDS WITH SUBMICRON METALLIC OXIDE PARTICLES , 1998 .

[28]  Jinliang Xu,et al.  Performance analysis of a parabolic trough solar collector using Al2O3/synthetic oil nanofluid , 2016 .

[29]  Mohd. Kaleem Khan,et al.  Performance enhancement of solar collectors—A review , 2015 .

[30]  K. A. Antonopoulos,et al.  The impact of internal longitudinal fins in parabolic trough collectors operating with gases , 2017 .

[31]  K. Gasljevic,et al.  Buoyancy effects on heat transfer and temperature profiles in horizontal pipe flow of drag-reducing fluids , 2000 .

[32]  Evangelos Bellos,et al.  Enhancing the Performance of Evacuated and Non-Evacuated Parabolic Trough Collectors Using Twisted Tape Inserts, Perforated Plate Inserts and Internally Finned Absorber , 2018 .

[33]  E. Bellos,et al.  Investigation of a star flow insert in a parabolic trough solar collector , 2018, Applied Energy.

[34]  M. Sheikholeslami.  CuO-water nanofluid free convection in a porous cavity considering Darcy law , 2017 .

[35]  E. Bellos,et al.  Thermal enhancement of parabolic trough collector with internally finned absorbers , 2017 .

[36]  A. Zeeshan,et al.  Mesoscopic simulation of CuOH2O nanofluid in a porous enclosure with elliptic heat source , 2017 .

[37]  Frank P. Incropera,et al.  Fundamentals of Heat and Mass Transfer , 1981 .

[38]  M. Siavashi,et al.  Two-phase mixture numerical simulation of natural convection of nanofluid flow in a cavity partially filled with porous media to enhance heat transfer , 2017 .

[39]  K. Khanafer,et al.  A critical synthesis of thermophysical characteristics of nanofluids , 2011 .

[40]  Saeed Zeinali Heris,et al.  First and second laws analysis of a minichannel-based solar collector using boehmite alumina nanofluids: Effects of nanoparticle shape and tube materials , 2014 .

[41]  Robert A. Taylor,et al.  Recent advances in modeling and simulation of nanofluid flows—Part II: Applications , 2019, Physics Reports.

[42]  D. Spalding.  A novel finite difference formulation for differential expressions involving both first and second derivatives , 1972 .

[43]  K. A. Antonopoulos,et al.  Thermal enhancement of solar parabolic trough collectors by using nanofluids and converging-diverging absorber tube , 2016 .

[44]  Assensi Oliva,et al.  Numerical simulation of wind flow around a parabolic trough solar collector , 2013 .

[45]  Peng Yu,et al.  Free Convection in a Porous Wavy Cavity Based on the Darcy-Brinkman-Forchheimer Extended Model , 2007 .

[46]  A. Ranjbar,et al.  Effect of using nanofluids on efficiency of parabolic trough collectors in solar thermal electric power plants , 2017 .

[47]  Josua P. Meyer,et al.  Thermodynamic optimisation of the performance of a parabolic trough receiver using synthetic oil–Al2O3 nanofluid , 2015 .

[48]  E. Bellos,et al.  Enhancing the performance of parabolic trough collectors using nanofluids and turbulators , 2018, Renewable and Sustainable Energy Reviews.

[49]  S. C. Mullick,et al.  An improved technique for computing the heat loss factor of a tubular absorber , 1989 .