| In this thesis simulation methods are used to study the non-equilibrium solidification, splat morphology and melt flow during thermal spraying. A micro/macro-integrated model has been developed to study the droplet deformation, melt flow, and wall interaction by integrating the melt flow with rapid solidification. A rapid solidification model is used to handle the non-equilibrium moving boundary problem with complicated interface conditions at the moving interface. A fluid flow model based on VOF schema captures free surface deformation and movement. The melt flow is incorporated into the rapid solidification model through a velocity profile fitting from the melt velocities at the correspondent macroscopic grids.; In the non-equilibrium model, the effects of the splat thickness, temperature, undercooling, thermal contact resistance, substrate materials and temperature on the rate of solidification are examined. The substrate melting is also quantified for various process conditions. Non-dimensional process map for substrate melting is presented to identify the critical conditions needed for onset of substrate melting.; Parametric studies are performed to investigate the effect of droplet size, impingement velocity, droplet temperature, substrate materials and temperature, thermal contact resistance, and wettability on the flattening ratio. The correlation between the flattening ratio and the Reynolds and Jakob numbers has been further improved to include the effect of the thermal conductivity of substrate on flattening ratio. The effects of solidification and wettability on the spreading are discussed. Spreading, splashing, and solidification of a Mo droplet on a stainless steel substrate has been simulated and the splashing morphology has been predicted.; A nucleation model has been developed to study the microstructure formation during thermal spraying. Undercooling, heterogeneous nucleation, and non-equilibrium solidification are taken into account. The effects of the substrate nature, initial temperature, interfacial thermal contact resistance, splat thickness, and wettability on the nucleation are investigated. |
