Enhancement of phase change material (PCM) based latent heat storage system with nano fluid and wavy surface

Abstract A numerical study is performed on the effects of surface waviness and nanoparticle dispersion on solidification of Cu–water nanofluid inside a vertical enclosure for different Grashof numbers. A geometry with sinusoidally curved wavy surface can be used to enhance heat transfer performance if it is carried out in an appropriate way. Therefore, the enclosure has wavy surfaces on right side with higher temperature and left side with lower temperature, while the top and bottom walls are both flats with insulated condition. Computations are conducted for the surface waviness ranging from 0 to 0.4, Grashof number from 104 to 106 and nanoparticle dispersion from 0 to 0.1. An enthalpy porosity technique is used to trace the solid and liquid interface inside the enclosure. To validate the results, the numerical solutions for special cases in a rectangular cavity were compared with previously published works which are in good overall agreement with those results. The numerical results show that for surface waviness of 0.25 and 0.4, a maximum of 60% decrease in solidification time for Gr = 106 is observed in comparison with Gr = 105 which indicates the increasing effects of natural convection on solidification due to distortion on surface. Therefore, surface waviness can be used to control the solidification time based on enhancing different mechanism of solidification.

[1]  Joel H. Ferziger,et al.  Computational methods for fluid dynamics , 1996 .

[2]  M. Abdollahzadeh,et al.  Free convection and entropy generation of nanofluid inside an enclosure with different patterns of vertical wavy walls , 2012 .

[3]  Mahdi Bayat,et al.  Control Volume Based Finite Element Method Study of Nano-fluid Natural Convection Heat Transfer in an Enclosure Between a Circular and a Sinusoidal Cylinder , 2013 .

[4]  Ali Akbar Ranjbar,et al.  Numerical heat transfer studies of a latent heat storage system containing nano-enhanced phase change material , 2011 .

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

[6]  Marcel Lacroix,et al.  Melting driven by natural convection A comparison exercise: first results , 1999 .

[7]  H. Johnstone,et al.  Heat and mass transfer in packed beds , 1955 .

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

[9]  Khamid Mahkamov,et al.  Solar energy storage using phase change materials , 2007 .

[10]  Shuying Wu,et al.  Thermal energy storage behavior of Al2O3–H2O nanofluids , 2009 .

[11]  M. A. Mansour,et al.  Free convection heat transfer in complex-wavy-wall enclosed cavity filled with nanofluid , 2013 .

[12]  J. Maxwell.  A Treatise on Electricity and Magnetism , 1873, Nature.

[13]  S. Mahmud,et al.  Free convection in an enclosure with vertical wavy walls , 2002 .

[14]  H. Bararnia,et al.  Natural convection between a circular enclosure and an elliptic cylinder using Control Volume based Finite Element Method , 2012 .

[15]  Jay M. Khodadadi,et al.  Effects of buoyancy-driven convection on melting within spherical containers , 2001 .

[16]  Vaughan R Voller,et al.  ENTHALPY-POROSITY TECHNIQUE FOR MODELING CONVECTION-DIFFUSION PHASE CHANGE: APPLICATION TO THE MELTING OF A PURE METAL , 1988 .

[17]  Arun S. Mujumdar,et al.  Enhanced heat transfer in free convection-dominated melting in a rectangular cavity with an isothermal vertical wall , 1999 .

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

[19]  S. D. Pohekar,et al.  Performance enhancement in latent heat thermal storage system: A review , 2009 .

[20]  Luisa F. Cabeza,et al.  Review on thermal energy storage with phase change: materials, heat transfer analysis and applications , 2003 .

[21]  Shohel Mahmud,et al.  Numerical investigation of natural convection inside a wavy enclosure , 2003 .

[22]  J. Rostami.  Unsteady natural convection in an enclosure with vertical wavy walls , 2008 .