Abstract
To increase the speed of solid front within semi-annulus geometry, two techniques were implemented including inserting fins connected to cold wall and loading alumina nanoparticles within the base PCM (phase change material). The annulus tank has three radial fins, and the limitation of water in view of low conductivity has been removed by means of dispersion of nanoparticles. The model of freezing consists of two coupled equations with overlooking velocity terms, and solution could be obtained via FEM (finite element method). The validation test was presented, and good accuracy was reported. The style of grid has been changed in various stages, and finer grid was utilized near the solid front. With the augment of concentration of alumina, the conduction becomes greater and period of discharging decreases around 31.81%. Another factor that was scrutinized in this paper is the size of powder that has optimized the value in which the lowest required time happens around 1568.32 s. As diameter (
d
p
) increases, the period of phenomena reduces around 14% and then it augments around 32%.