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Numerical and experimental investigation of paraffin wax melting in spherical cavity

  • Debasree GhoshEmail author
  • Chandan Guha
Original
  • 41 Downloads

Abstract

Various process parameters influence the melting and solidification phase change process. Studies on the influence of shape of cavity, thermo-physical properties of the phase change material and the boundary conditions, on the phase change process, has been carried out by various researchers worldwide. The effect of the thermal properties of the cavity material on the process is yet to be investigated thoroughly. In this work, melting process of paraffin wax is simulated in a spherical cavity for various cavity materials having different thermal properties and for different boundary conditions. The simulations results are obtained using enthalpy-porosity model for free surface melting process, solved using Ansys-fluent 16.2. Experimental studies were carried out for one type of cavity material. The experimental investigation included visualization of shape of solid fraction which is used to validate the numerical approach of this computational study. The results showed that the materials having higher thermal diffusivity has enhanced melting rate because of increased bouncy effect and convection. It has been found that the higher Stefan number shows the effect of higher natural convection and maximum velocity profile, resulting in enhanced melting process. These simulations are significant for selection of cavity material for different processes like energy storage, melting-solidification of metal in casting and others.

Symbols

αn

Phase volume fraction of nth fluid

ui

Velocity component in ith direction (m/s)

xi

Cartesian component

t

Time (s)

ρ

Density of PCM (kg/m3)

μ

Viscosity of PCM (kg.m/s)

Cpl

Specific heat of liquid pcm (J/kg.K)

p

Pressure (N/m2)

gi

Gravitational force (m/s2)

Si

Momentum source (kg/m2.s2)

h

Enthalpy (kJ/kg)

k

Thermal conductivity (W/m.K)

T

Temperature (K)

Tw

Wall temperature of the cavity (K)

Tm

Mean melting temperature of PCM (K)

C

Mushy zone constant

γ

Liquid fraction

Ts

Solidus temperature (K)

Tl

Liquids temperature(K)

Α

Thermal diffusivity (m2/s)

St

Stefan number

Notes

Compliance with ethical standards

Conflicts of interest

There are no potential conflicts of interest with regard to publication of this paper.

Human participants and/or animals

Research did not involve Human Participants and/or Animals.

Consent

Consent to submit has been received explicitly from all co-authors.

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Chemical EngineeringBirla Institute of TechnologyRanchiIndia
  2. 2.Department of Chemical EngineeringJadavpur UniversityKolkataIndia

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