Free boundary problem from stochastic lattice gas model

We consider a system consisting of two types of particles called "water" an d "ice" on d-dimensional periodic lattices. The water particles perform exc luded interacting random walks (stochastic lattice gases), while the ice pa rticles are immobile, When a water particle touches an ice particle, it imm ediately dies. On the other hand, the ice particle disappears after receivi ng the lth visit from water particles. This interaction models the melting of a solid with latent heat, We derive the nonlinear one-phase Stefan free boundary problem in a hydrodynamic scaling limit. Derivation of two-phase S tefan problem is also discussed. (C) Elsevier, Paris.