An Investigation of the Cold Gas Dynamic Supersonic Spray Process Particle/Flow Field

This research was conducted in collaboration with Centerline (Windsor) Ltd. It involved a study of the Cold Gas Dynamic Spray (CGDS) process for metal deposition using supersonic jets. A computational fluid dynamic model of the process was developed. The gas dynamic flow field and particle trajectories within an oval shaped supersonic nozzle, near the impact target as well as in the jet that forms in the immediate surroundings of the nozzle exit was predicted. The flow field calculation inside the nozzle was found to be in good agreement with a series of pressure measurements at the nozzle wall. In addition, predicted particle velocity results at the nozzle exit were compared with the experimental data obtained from a forward-scatter laser Doppler anemometer (LDA) with frequency shifting capability. The numerical results are in qualitative agreement with the velocity profiles along the major and minor axis at the nozzle exit.

The results are used to determine the details of the pattern of particle release into the surroundings. The locations and concentrations of particles leaving the boundaries of the domain of interest are determined and presented in a graphical manner that is easy to interpret. This information is important in the design of particle collection equipment to be used in the process.

Mo Karimi successfully defended his M.A.Sc. thesis, based on this work, in the Fall of 2005.