|
5727 |
|
Friday, June 09, 2017, Hall 28 9:20 AM Modeling & Simulation II |
|
Twin wire arc torch with optimized flow parameters |
|
Amirsaman Farrokhpanah / University of Toronto, Canada Larry Pershin/ Centre for Advanced Coating Technologies (CACT), University of Toronto, Javad Mostaghimi*/ University of Toronto, Canada |
|
Wire arc spraying, being an efficient and cost effective thermal spray technique, has many industrial applications. In this process, flow of gas, commonly air at a high velocity is used to atomize molten metal wire tips that have been created by an electric arc. Both the arc and the torch geometry play key roles in providing of desired conditions for molten droplets to form a quality coating. In the current study, numerical solutions have been used to modify the inner geometry of an industrial wire arc torch (HD 456, Thermion, US). The goal is to minimum energy loss and enhance atomization of the molten droplets. Since the torch is operated at high gas velocities, results show that small improvements in hydrodynamic design can significantly improve efficiency. The numerical torch model here also includes a particle tracking module that helps in better understanding the effects of changes in torch geometry on the particle velocities and temperatures. Based on the numerical optimization, a new air cap for the torch has been machined and tested. A feedstock of 316 stainless steel wires has been used. Particles' trajectory, velocity and temperature are compared using DPV2000 monitoring system and a high speed camera. The deposited coatings microstructure, deposition efficiency and surface morphology have also been compared. The results show that the modified torch generates better focused particles plume at 150mm spray distance. The average coating porosity is reduced by 1.3-2.0% while deposition efficiency has increased by 7.3%. |