Simulation of heat and mass transfer in domain of solidifying binary alloy

In the paper the mathematical description, numerical algorithm and also the example of spherical casting solidification are presented. The casting is made from binary alloy (Cu-Zn). It is assumed that the solidification tempe rature is time-dependent and it results from the alloy component concentrat ion near the solidification front. The course of macro-segregation phenomen on is modelled using the mass balances at the set of control volumes distin guished in domain of the casting considered. The mass balances are formulat ed under the assumption of the instant equalization of composition in liqui d and solid state (the lever-arm model). The Scheil model (the instant equa lization of alloy component concentration in liquid state and the omission of diffusion in solid state) is also analyzed. On the stage of numerical co mputations the combined variant of the boundary element method (BEM) [1, 2, 3] supplemented by the alternating phase truncation method (APTM) [4, 5] i s used. The additional new element of the algorithm proposed is the applica tion of the BEM algorithm for objects oriented in rectangular co-ordinate s ystem to numerical modelling of diffusion processes proceeding in spherical domains.