Theoretical modeling and optimization study of particle acceleration and heating inside an electrothermal-chemical device

A theoretical model for the physical phenomena taking place in a new electrothermal-chemical device for thermal-spray coating is proposed. Inside this new device, the powder particles to be coated on various substrates are accelerated and heated by a mixture of plasma and gases that results from the burning of an energetic propellant. The model is meant to be a tool for the device work optimization in order to obtain high quality coatings. The equations are able to describe the hydrodynamic and thermodynamic characteristics of the accelerating gas as well as those of the accelerated particles. The results we obtained point to some special features of our thermal-spray device that are not common to other methods and devices currently in use. In the same time, it seems that using our model predictions, we may have the possibility to choose the proper input process parameters which would lead to optimal thermal and kinetic characteristics of the accelerated particles at the device exit and finally to quality coatings. The model predictions for some flow and particle parameters such as: gas pressure and particle velocity, are in good agreement with the experimental data.