Prediction of Particle Velocity for the Cold Spray Process

Report No. ARL-TR-5683
Authors: Victor K. Champagne; Surya P. G. Dinavahi; Phillip F. Leyman
Date/Pages: September 2011; 24 pages
Abstract: The ability to predict particle velocity is key to the prediction of cold spray performance. Individual particles must exceed a material dependent critical velocity in order to deposit and form a coating. Particle velocities can be calculated from the drag relationship between the particle and flowing gas. The relative accuracies of a one-dimensional (1-D) calculation vs. a two-dimensional (2-D) calculation, in comparison to measured values, would help determine whether the simple 1-D calculation can be used instead of the more complicated 2-D calculation. Both types of calculation were performed for a given nozzle and compared with measured values. It was found that the 1-D calculation resulted in velocities about 7% higher than measurement, while 2-D calculations yielded velocities 7% lower than measured values. The 2-D calculation yields more information, but the fast, convenient 1-D calculation has adequate information and accuracy to be used for most particle velocity calculations.
Distribution: Approved for public release
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Last Update / Reviewed: September 1, 2011