The working group develops physical mathematical-numerical descriptions of manufacturing processes by means of analytical models and finite element simulations. Understanding the processes leads to simplifications and improved properties.
IEK-1 starts by realizing process simulations by means of ANSYS and finite elements.
Processes with thermal plasmas have already been proven in a multitude of technical areas. For the further development of technologies based on thermal plasma and the manufacture of new thermally sprayed surfaces, a better quantitative understanding of thermal spraying processes is required. Modelling plasma burners with direct current arc and jet properties is, however, a great challenge which requires state-of-the-art simulations by means of computational fluid dynamics (CFD).
Low-pressure plasma spraying thin films (LPPS-TFs) were recently numerically simulated at IEK-1 by F. Qunbo by means of the CFD program FLUENT. The temperature, velocity, pressure, and density fields were calculated under typical operating conditions for the deposition of thermal barrier coatings. On the basis of plasma flow fields, it was also possible to calculate plasma trajectories, melting temperatures, and the degree of evaporation of ZrO2 particles with typical grain size distribution. This revealed that, almost immediately after exiting the injection nozzle, all particles melt completely. The evaporation rate is primarily determined by the initial particle size, the injection spray angle, the injection location, and the composition of the plasma.
This type of simulation will in future be applied to a greater bandwidth of plasma operating conditions and to other materials such as LaSrFeCoO3 (utilized for tight membranes for the separation of oxygen and hydrogen), and it will be complemented by kinetic Monte Carlo simulations of the morphology of the resulting coatings.