The use of computational fluid dynamics (CFD) to model the operation of thermal spray processes has gained interest in the thermal spray community, able to provide an understanding as to how a process functions, and better yet how to make a process work better. Advancements to the science of modeling now permits the ability to create a comprehensive model of a plasma gun that not only simulates the dynamics of the gas but also the mechanics of arcs (plasma), thermodynamics, and entrained particulates to form a nearly complete model of a working thermal spray process. Work presented includes the methods and procedures used to validate the model to a Sulzer Metco TriplexPro 200 plasma gun and exploration of the operating regime to give an in depth and insightful look into the physics behind the operation of a triple arc cascaded plasma gun.

Utilization of a comprehensive validated computer model of a thermal spray process enables an ability to improve, optimize, and fine tune the performance of that thermal spray process. A validated model of the Sulzer Metco TriplexPro 200 plasma gun has been used to improve the performance of the actual gun in terms of enhancing gas flow dynamics, thermal management, and overall performance in terms of a robust design. Internal changes to the gun geometry using the model have extended the life of the hardware beyond any current plasma gun. In addition the model has permitted the investigation of the fundamental operation of the gun, specific to the behavior and path of the arcs, as well as the ability to operate the plasma gun, under simulation, in operating regimes that currently cannot be supported by the physical hardware. The model has been run at gas pressures above 14 bar and/or voltages above 300V that currently cannot be obtained with the physical hardware due to equipment limitations to evaluate the potential to extend the operating window of the Sulzer Metco TriplexPro 200 gun beyond current levels in terms of particle velocity and temperature. The end result is an improved process tool for applying thermal spray coatings from high temperature ceramics to relatively colder and faster carbides and alloys.