Numerical modeling of melting and dripping process of polymeric material subjected to moving heat flux: Prediction of drop time

Numerical simulations are carried out in order to predict drop-size and -time of molten polymer during fire. Mass, momentum and energy conservation equations are solved in a 2-D system based on a fixed grid by means of a finite volume method. The Volume of Fluid (VOF) method and the Enthalpy-Porosity method are applied to model the deformable polymer-air interface and the melting processes, respectively. Results successfully show the dynamic behavior of the molten polymer and the effect of the deformation on the melting process. It is found that the total heat flux at the melting front which directly controls melting speed is linearly correlated with the length of the melting front during frequent accumulation and dripping of molten polymer even if the inclination angle is varied. Drop-size and -time can be estimated by a simple force balance equation at the polymer-air interface, and show a linear correlation with a modified inverse Bond number and with a combined Capillary number and modified Bond number, respectively.