DC plasma spraying: Effect of arc root fluctuations on particle behavior in the plasma jet

In D.C. plasma spraying, plasma guns involve a continuous movement of the a re root on the anode wall. This movement causes fluctuations in are voltage and net enthalpy input to the flow and, instabilities in the jet flow. The latter are enhanced by the development of turbulence in the shear layer be tween the flow and the surrounding gas at rest, and by the mixing with the ambient gas. This paper addresses the effect of short-term flow fluctuation s on the behavior of particles injected in the flow. The study was carried out using both numerical and experimental techniques. It shows that particl e trajectory and, therefore, acceleration and heating can be affected by je t flow fluctuations. However, further experiments and calculations are requ ired to have a better understanding of the effect on coating properties.