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| Abstract No.: |
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Scheduled at:
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Monday, May 03, 2010, Olivia Room 2:40 PM
HVOF 1
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| Title: |
Computational investigation of warm spray
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| Authors: |
Sai Gu* / University of Southampton, UK
Hani Tabbara / University of Southampton, UK
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| Abstract: |
HVOF thermal spraying is able to generate a high momentum output with a relatively low carrier gas temperature, in the region of 3000 K. This gives HVOF its unique ability to produce dense, low porosity coatings. The supersonic gas flow through a cold gas spray gun is in some extent similar to the HVOF, especially when hot gas is used. In the near future a new hybrid thermal spray technology could be developed to overcome the constraints of both processes today.
In this study advanced computational models have been developed to thoroughly examine the design of HVOF and cold spraying. As a first step, various geometric design parameters have been analyzed, including the influence of kerosene fuel droplet size on the flame shape and combusting gas flow for HVOF. For cold spray, the effect of particle size and carrier gas type on the gas flow, the spray powder distribution and the particle velocity variation at the exit has been assessed.
A further fundamental study looks into the effect of particle mass loading on the gas flow through the cold spray system by adopting the method of two-way coupling between the gas and particle phases. With an increasingly high concentration of powder within the two-phase mixture a stochastic collision model is appropriately developed to account for particle-particle interactions and to accurately track their subsequent trajectories.
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