Parametric Study of Exhaust Pattern in Cold Spray Using CFD and Particle-Wall Impact Analysis

A numerical simulation of a cold gas dynamic spray process using a computational fluid dynamic (CFD) technique is presented. Distribution of particulate matter in the immediate surroundings of spray application site is of interest. The flow field inside an oval shaped supersonic nozzle and the surroundings of the nozzle is simulated. Particle trajectories along their flight in the nozzle as well as before and after impact with the target plane are calculated. Fluent is used for the purpose of flow field simulation. A discrete-phase Lagrangian particle trajectory model is used for particle trajectory calculation. A model uses the principles of motion and impact dynamics to predict particle behavior upon impacting the substrate. The locations and concentrations of particle exhaust patterns around the impact location are determined and presented graphically. The dependence of these patterns to variations in the jet-target tilting angle, standoff distance, upstream temperature and particle material is investigated.