Numerical study on melt underwater spreading with MPS method

•An extension of MPS method is developed to model the specific phenomena appearing in melt spreading over substrates under a water layer, such as multiphase flow and film boiling heat transfer.•The film boiling heat transfer is calculated along the film boiling regime of the boiling curve by removing the heat form the top of melt to the surrounding water.•The updated MPS code is employed to simulate two melt spreading tests, showing that the code could predict the melt spreading length and melt thickness well.