Discussion Forum

Hello everyone, I have developped a numerical model for the combustion of iron rods ignited at their base with a laser beam and placed in an oxygen atmosphere, for that i'm using the phase field method, the problem we are facing is that at the bottom of the sample, we should have a diffusion of oxygen in liquid iron, but also have a diffusion of iron inside the oxygen phase, since we are not modelling the transport of mass we shouldn't have that, the only way we are modelling the vapor is by a heat loss. The main problem is that this diffused metal below the sample is getting the oxygen away from the sample, thus reducing the oxygen incorporated in the liquid iron and the global reaction rate, can anyone tell me what is this diffused element ? how to get rid of it or make it so that it does not displace the oxygen below the sample ? Thanks in advance, i have attached below a picture of an oxygen concentration field.