Numerical study on the importance of the mixed convection and the impact of the cooling rate on the solidification of a pure material

Abstract

The present paper investigates numerically the solidification process of a pure metal, injected inside a channel, aiming to overview theoretically this complex phase change process, using COMSOL Multiphysics. The study is based on the Voller and Prakash model with fixed grid technique. Results interpretation have been steered toward guessing the effect on the whole process of a varying entrance melt velocity; having proven that melt flow has a negative effect on the solidification rate. Also, the decreasing mid values of temperature transition (MVTT) would give fine numerical solution because it offers less thick mushy zone; this allows a good understanding to the solidification rate, mushy zone spreading and flow structure nearby solid region. Then, two different variable cooling rates functions were suggested comparing them to constant heat flux case. Results indicate that linear function cooling heat flux is the best function in terms of economy of cooling costs.