ON THE SPREADING AND SOLIDIFICATION OF MOLTEN PARTICLES IN A PLASMA SPRAY PROCESS - EFFECT OF THERMAL CONTACT RESISTANCE

The spreading and simultaneous solidification of a liquid droplet upon its impingement onto a substrate permitting thermal contact resistanc e has been numerically simulated; the effect of contact resistance and the importance of solidification on droplet spreading are investigate d. The numerical solution for the complete Navier-Stokes equations is based on the modified SOLA-VOF method using rectangular mesh in axisym metric geometry. The solidification of the deforming droplet is consid ered by a one-dimensional heat conduction model. The predictions are i n good agreement with the available experimental data and the model ma y be well suited for investigating droplet impact and simultaneous sol idification permitting contact resistance at the substrate. We found t hat the final splat diameter could be extremely sensitive to the magni tude of the thermal contact resistance. The results also show that for the condition of higher Reynolds and/or higher Stefan numbers the eff ect of solidification on the final splat diameter is more important.