Positioning angle effects on the melting time of a tall rectangular enclosure; using the Lattice Boltzmann method

The melting process of phase change materials (PCM) in a tall rectangular enclosure with a variable positioning angle has been numerically investigated using a D2Q9 enthalpy based Lattice Boltzmann method. The enclosure with the aspect ratio of 0.5 is heated isothermally on one side, while all other sides are thermally insulated.An immersed moving boundary condition is employed to model the interface between liquid and solid phase. Three positioning angles of0°, 45° and 90°, which produce relatively different melting patterns, are considered. The time variations of the melting line, flow patterns in themelt pool, and temperature distribution are thoroughly examined. The results indicate that changing the positioning angle leads to noticeablevariations in flow and melting patterns, which are more pronounced at higher inclination angles. Moreover, it was found that the total meltingtime decreases almost linearly by increasing the positioning angle, such that there are about 17.5 and 36 percent reductions in total melting timeas the positioning angle increases to 45o and 90o, respectively. Therefore, heat transfer operation of melting PCM systems can be simply controlled by the enclosure orientation.

Keywords:

Melting process , Phase change material (PCM) , Free convection , Melting time , Lattice Boltzmann Method (LBM)