Figure (10) displays the temperature contour over time during the solidification process. Initially, the temperature of the melted PCM decreases, causing the hotter PCM to rise to the top. The overall temperature of the melted PCM reaches the solidus temperature, achieving a uniform temperature distribution at around 500 seconds for all three models. At this stage, a solid layer forms on the fin surface. The temperature of this layer decreases to match the heat transfer fluid temperature during solidification, and the layer width gradually increases until full solidification is achieved.
Figure (11) displays the temperature versus time graph, showing the volume averaged PCM temperature over time. Two distinct regions are observed. The first region is characterized by a rapid decrease in temperature over time, primarily driven by sensible heat transfer from the PCM. This region concludes at around 500 seconds, corresponding to stage one in the temperature contour. The second region exhibits a gradual decrease in temperature over time due to heat transfer by latent heat, continuing until the end of the test.
There are slight differences among the three models, with Model A-1 having slightly lower temperatures at certain instances, particularly at the beginning of region two. Model A-2, on the other hand, features the highest temperatures in region two.