Effect of Viscoelasticity on the Solidification and Melting of a Phase Change Material

In the current work, we simulate the solidification of a phase change material (PCM) inside a square cavity. We consider two different cases: (i) the solidification of a Newtonian fluid and (ii) the solidification of a viscoelastic fluid. The objective is to study the effect of viscoelasticity on the solidification pattern of the fluid. The enthalpy-porosity approach is used for modeling the solidification phenomenon. The log conformation approach is used to calculate the viscoelastic stresses in a stable manner. The numerical method used is second-order accurate in space and time. The results indicate that the viscoelasticity present in the fluid promotes the solidification processes. This can be partly attributed to the extra polymer viscosity and partly due to the elastic stresses present in the viscoelastic fluid. Due to the viscoelastic nature of the fluid, smaller fluid velocities are created in the domain under natural convection. As a result, the hot fluid is circulated at a slower rate in the domain causing faster solidification. The results also show higher values of viscoelastic stresses near the liquid–solid interface and near the hot wall.