No abstract

In the present work a fundamental numerical model is implemented in the open source framework, finite volume method (FVM) based computational fluid dynamics (CFD) program OpenFOAM®, to tackle the solid-liquid phase change phenomena in the presence of gas phase. The volume of fluid (VoF) method is employed to distinguish between the phase change material (PCM) and the gas phase, and the enthalpyporosity method is adopted to capture the moving boundary phase change phenomena in the PCM. The discussed model is validated against the well documented cases in the literature i.e., 1D Stefan problem, melting of gallium and free surface thermocapillary flow with phase change. The simulation results are in very good agreement with those found in the literature. Finally, experiments are performed with partially filled paraffin wax (Rubitherm® RT31) in the presence of air in an enclosure. The left and right walls of the enclosure are made of aluminum plates and maintained at different temperatures while the remaining walls are made of Plexiglas. The temporal evolution of the melting front during melting obtained from the discussed numerical model is compared with experiments.

The solid-liquid phase front inside the mould progresses from the rail end towards the weld centre and from rail base to rail head, such that the temporal and spatial evolution of the solid-liquid phase front results in a V-shaped solidification.Finally, the simulation results are qualitatively compared with experiments conducted at Goldschmidt Holding GmbH. The predicted temperature profiles in the rail during preheating and cooling stage, fusion zone (FZ) and heat-affected zone (HAZ) have shown a good agreement with experiments.

In the present work a fundamental numerical model is implemented in the open source framework, finite volume method (FVM) based computational fluid dynamics (CFD) program OpenFOAM®, to tackle the solid-liquid phase change phenomena in the presence of gas phase. The volume of fluid (VoF) method is employed to distinguish between the phase change material (PCM) and the gas phase, and the enthalpy-porosity method is adopted to capture the moving boundary phase change phenomena in the PCM. The discussed model is validated against the well documented cases in the literature i.e., 1D Stefan problem, melting of gallium and free surface thermocapillary flow with phase change. The simulation results are in very good agreement with those found in the literature. Finally experiments are performed with partially filled paraffin wax (Rubitherm® RT31) in the presence of air in an enclosure. The left and right walls of the enclosure are made of aluminium plates and maintained at different temperatures while the remaining walls are made of Plexiglas. The temporal evolution of melting front during melting obtained from the discussed numerical model is compared with experiments.