Computational fluid dynamics simulation of splat formation process in plasma spraying

A 3D computational model of the splat formation process was established to simulate the flow,heat transfer and solidification of a Ni droplet impacting on the surface of mild steel substrate with the computational fluid dynamics(CFD) software Fluent.The governing equations were discretized according to typical finite volume method(FVM).A volume of fluid(VOF) tracking algorithm was used to track the droplet free surface.Meanwhile,the simulated results were visualized.The results indicated that the maximum pressure was found at the impact point at the beginning of impact.The pressure distribution inside the deformed droplet during the spreading which came from the impacting was in the shape of a mushroom cloud,and the impact pressure decreased from the impact point to the top side of the droplet.The fluid spreaded radially outward during flattening which was accompanied by impact,consequently two symmetrical vortices appeared in the velocity vector field.Correspondingly,the temperature distribution in the deformed droplet exhibits'camel-hump'shape associated with the combined interaction of the substrate conductivity and convective heat transfer of the melt droplet.The occurrence time of the maximum spreading velocity raised from the impacting delay of 0.03 μs compared with that of the maximum impact pressure.