This case demonstrates the melting of ice. It’s a example of phase change process. The present case uses a multi-region approach to simulate the phase change process. The simulation is carried out in OpenFOAM v1906 using the solver chtMultiRegionFoam and the phase change is handled by solidficationMeltingSource source term. The geometry is a 2-D pipe and the flow is laminar and transient. The volume fraction of melting water is obtained from the simulation and is analyzed.