Enhanced models of heat sources in welding and plasma spraying: Examples of thermal plasma models

Abstract

Several multi-scale models of thermal plasma produced both by arcs in TIG and PAW welding and used in plasma spraying are analyzed here from the perspective of mathematical modeling of the complex problem of energy transfer from the plasma to a work-piece. Such analysis is desirable before making a decision about the development of new software or a critical evaluation of available commercial software. The evaluation of transferred energy plays a key role in the numerical simulation of welding with solid phase transformations, analysis of hydrodynamic effects in a weld-pool, and simulation of micro-contacts of impinging granules and substrate in plasma spraying. Unfortunately, energy dissipation effects, which occur in a weld-pool, are omitted here and they require the further consideration. Simple one-dimensional theories are presented in the descriptive manner but multi-dimensional models of plasma are shown as schemes with tables of assumptions and boundary conditions.