| Particle-laden flow has been acknowledged as an important phenomenon integral to many technological and natural systems. Analysis of a high speed particle-laden flow typical of those in the high velocity oxy-fuel (HVOF) process is presented in this thesis. Since the particulate flow in this process includes a large variety of particle suspension, the Lagrangian and Eulerian approaches have been applied in parallel to simulate the two-phase flow associated with the process.; Effects of attaching a cylindrical shroud to the end of the supersonic HVOF nozzle on gas and particle flows have been analyzed. It was found that the shroud significantly reduces the oxygen content in the field by protecting the supersonic jet from ambient air entrainment. The validation experiments were performed for the majority of process parameters such as shock formation, particle conditions, and coating oxygen content.; The thesis concludes with application of the numerical models in designing a nozzle that provides improved performance in the areas of deposition efficiency, particle in-flight oxidation, and flexibility to allow coating of ceramic powders. And finally, the new nozzle was built, and successfully tested with several coating materials including metallic, carbide, and ceramic powders. |
