Computational Modeling and Empirical Testing of Material Feed Transport Systems

The characteristics and operating regime of particulate transport using a carrier gas is investigated and evaluated related to thermal spray powder feed hose transport systems in a computational fluid dynamic model.  Comparisons between the CFD model and actual powder feed hoses validated the model and explored the flight conveying operating regimes for powder flow in a hose.  The importance of particle interaction as well as the affects of hose geometry is clearly evident in the model results.  The causes of pulsation and clogging in powder hoses are identified along with some counter-intuitive findings.   Insight to the advantages and limitations of material feeding in thermal spray processes provides some physical answers to the observed instability with powder feeding.  Identified operating characteristics enables improvement to the art of powder feeding through better understanding of the entire feed system and the resulting interactions between the powder feeder, powder feed hose, and powder injector.