A computational examination of the sources of statistical variance in particle parameters during thermal plasma spraying

Computational modeling is used to systematically examine many of the source s of statistical variance in particle parameters during thermal plasma spra ying. Using the computer program LAVA, a steady-state plasma jet typical of a commercial touch at normal operating conditions. is first developed. The n, assuming a single particle composition (ZrO2) and injection location, ve al world complexity (e.g., turbulent dispersion, particle size and density, injection velocity and direction) is introduced "one phenomenon at a time" to distinguish and characterize its effect and enable comparisons of separ ate effects. Calculations are also performed wherein all phenomena are cons idered simultaneously to enable further comparisons. Both nonswirling and s wirling plasma flow firm's are considered. Investigating each phenomenon se parately provides valuable insight into particle behavior. For the typical plasma jet and injection conditions considered particle dispersion in the i njection direction is most significantly affected by (in order of decreasin g importance). particle size distribution, injection velocity distribution, turbulence, and injection direction distribution or particle density distr ibution. Only the distribution of injection directions and turbulence affec t dispersion normal to the injection direction and are of similar magnitude in this study. With regards to particle velocity and temperature, particle size is clearly the dominant effect.