- Gallium melting in a rectangular container with a heated side face has been investigated. The focus of the research is the advancement of the numerical model to 3D status taking into consideration thermal vari-ations of medium properties and the presence of mushy zone, and the model experimental verification using known data and new data obtained on a specially developed experimental setup. This setup is ori-ented to trace the liquid–solid interface position and profile and melt velocity using ultrasonic Doppler velocity measurements in the liquid phase. The numerical model was based on COMSOL Multiphysics software. 2D and 3D versions were built to calculate the melting regime and the flow process characteristics. Outputs of both versions were com-pared with known experimental data and new data obtained in the present study. The results revealed a better agreement between 3D computational and experimental data indicating to a profound effect of the container boundaries on the problem under study.