SOLIDIFICATION OF PCM AROUND A FINNED TUBE: MODELING AND EXPERIMENTAL VALIDATION

This paper presents the results of an investigation on axially finned tubes to enhance the processes of charging and discharging thermal storage units. The proposed model is based upon pure conduction in the solid and liquid phases. The enthalpy approach and the finite volume method were used in the numerical treatment. The Alternating Direction Implicit scheme (ADI) was used together with finite difference to discretize the differential equations and the associated initial and boundary conditions. The grid points and the time step were optimized. The numerical predictions were compared with experimental results and relatively good agreement was observed. It was found that increasing the radial length of fins or their number enhances solidification and reduces the time for complete phase change. The increase of the symmetry circle radius was found to increase the complete solidification time while the increase of the fin thickness showed little influence on the solidification process.