Effect of Magnetic Force on Heat Transfer Increasing in PCM Slurry Flow

Document Type : Original Research Paper




The temperature of the phase change material remains almost constant when the phase changes. It means that these materials have a high heat capacity during phase change. This property causes the particles containing these materials to act like distributed heat sinks throughout the field and result in heat transfer increment. However, if these particles are placed inside the thermal boundary layer, they will have a greater impact on the heat transfer rate. The vertical velocity component in the entrance length, prevents particles from being placed near the wall. On the other hand, in this study, the particle coating is iron oxide, which are able to move towards the wall by magnetic force. This magnetic field pulls the particles toward the heated wall and inside the thermal boundary layer. To solve the governing equations, two-phase Eulerian-Lagrangian model has been used. The PCM is Paraffin wax with 30 microns diameter and, particle volume concentration is 10%. This study covers a wide range of Reynolds numbers (100<Re<500), subcooling numbers up to 0.75 and magnetic field strength (H0) up to 2.1e-8 A.m-1. The results show 16.56% increase in Nusselt number for Re=100 and, H0=2.1e-8 A.m-1.