A model of the shock-wave induced spray process (SISP) and the criteria for bonding are used to predict whether particles traveling within the unsteady flow regime will adhere to the substrate upon impact. The results are then used to predict if a coating can be formed under specific spraying conditions. Having been validated based on particle velocity measurements, the model is used to investigate the effect of varying spray parameters, such as powder and gas initial temperature, gas heater length, and spray frequency.

Computational Fluid Dynamics (CFD) is used to model the Shock-wave Induced Spray Process (SISP). SISP utilizes the kinetic and thermal energy induced by a moving shock-wave to accelerate and heat powder particles, similar to Cold Gas-Dynamic Spraying (CGDS), where the particles impact the substrate and deform plastically to produce a coating. Individual powder particles reach the substrate at different velocities and temperatures depending on their location within the unsteady flow regime. The critical velocity correlated to particle impact temperature and a CFD model are used to predict whether a particle traveling within this unsteady flow regime will bond to the substrate upon impact or bounce off. This information is then used to predict if a coating can be formed under a specific set of spray conditions.

A computational fluid dynamic (CFD) model of the cold gas dynamic spray process is presented. The gas dynamic flow field and particle trajectories within an oval shaped supersonic nozzle as well as in the immediate surroundings of the nozzle exit, before and after the impact with the target plane, are simulated. Predicted nozzle wall pressure values compare well with experiment. In addition, predicted particle velocity results at the nozzle exit are in qualitative agreement with those obtained using a side-scatter laser Doppler anemometer (LDA.) Details of the pattern of particle release into the surroundings are visualized in a convenient manner.