Constrained and unconstrained melting inside a sphere

The melting of the phase change material (PCM) inside a sphere using n-Octadecane for both constrained and unconstrained melting is investigated. In constrained melting, the solid PCM is restrained from sinking to the bottom of the sphere. For unconstrained melting, the solid PCM would sink to the bottom of sphere due to gravity. The experiments are carried out at three different wall temperatures of 35 °C, 40 °C and 45 °C with a sub-cooling of 1 °C for the unconstrained melting and three different initial sub-cooling of 1 °C, 10 °C and 20 °C at a constant wall temperature of 40 °C for the constrained melting.