Diffusion controlled and convection dominated vaporization

The material removal by an intense power source is modeled. The vaporization rate is governed by the heat transfer within the substrate. Both convection dominated and diffusion controlled vapor removal are examined. Langmuir's model for vapor removal rate is also studied. The vaporizing temperatures and material removal rates subject to an intense power are obtained. It is found that the material removal rates are about the same regardless of the vapor removal models used. The diffusion controlled model, however, predicted a considerable higher vaporizing temperature. It is found that for most material removal process, the bulk flow motion driven by the pressure difference (convection dominated) is the predominant mechanism of vapor removal. Langmuir's model predicts the highest material removal but not much higher than that predicted by the convection dominated model.