Using the interface Peclet number to select the maximum simulation interface width in phase-field solidification modelling

This study investigates the use of interface Peclet number P = w/(Dl/Vtip), to determine the interface width (w) used in phase-field simulations, where Dl is the liquid diffusivity and Vtip is the tip velocity. The maximum simulation interface width (wmax) under varied growth conditions was analysed via convergence analysis and it was found that there is a limit of P for the maximum interface width at various velocities. Converged results can be obtained only when w < wmax = 0.075Dl/Vmax where Vmax is the maximum growth velocity during transient solidification. The effect of the inclusion of finite solid diffusivity on the P limit in selecting wmax was analysed, and little influence was observed.

► We propose to use of the interface Peclet number to determine the interface width in phase-field solidification modelling.
► We found that convergent results can be obtained when P ⩽ 0.075 at any velocity.
► We found that inclusion of finite solid diffusivity has little effect on P limit on wmax.