TLM TREATMENT OF A GENERAL DIFFUSION FLUX BOUNDARY-CONDITION

An approach of using a current-controlled voltage source analogy to ac count for a general boundary condition of particle or thermal flux in transmission-line matrix (TLM) diffusion modelling has been developed. For mass diffusion, this boundary condition is expressed as D partial derivative C/partial derivative x + alpha C = 0, where C is the conce ntration, D is the diffusion coefficient, and alpha is a parameter cha racterizing the out-diffusion mobility across the boundary of interest . Confirmation of the TLM numerical treatment through comparison with analytical solutions is presented. Besides the open-circuit and short- circuit boundaries, the matched-load boundary is also found to be a sp ecial case of the present boundary condition. This extension of the bo undary treatment allows the highly flexible TLM method to be applied t o a greater variety of diffusion problems.