Super-cooling effects and solidification of water inside a horizontal cylinder with a rough, sinusoidal surface shape

We examined how the outer shape of a cylindrical capsule, and the quantity of super-cooling, influenced the charging performance of a phase change material (water). The numerical method was validated using previous research and showed good agreement. Higher amplitude of roughness of the capsule shape was affirmed to affect solidification performance with or without super-cooling. The capsule with higher amplitude had an advantage in solidification performance, not only by increasing the heat transfer rate inside the capsule but also by reducing the quantity of super-cooling. Small super-cooling (delta T-Smooth Surface = 4 C) shows less impact (only 1%), while large super-cooling (delta T-Smooth Surface = 8 C) shows a prominent impact (10%) on the delay of solidification time. Typical results with no super-cooling and with super-cooling (delta T-Smooth Surface = 8 C) showed 10% and 15% shorter solidification time, respectively, for optimal shape with n = 6 compared to a matching smooth capsule (pi = 0).