OpenFOAM Modeling of Particle Heating and Acceleration in Cold Spraying
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OpenFOAM Modeling of Particle Heating and Acceleration in Cold Spraying K.-H. Leitz1 • M. O’Sullivan1 • A. Plankensteiner1 • H. Kestler1 • L. S. Sigl1
Submitted: 14 July 2017 / in revised form: 6 September 2017 / Published online: 25 September 2017 Ó ASM International 2017
Abstract In cold spraying, a powder material is accelerated and heated in the gas flow of a supersonic nozzle to velocities and temperatures that are sufficient to obtain cohesion of the particles to a substrate. The deposition efficiency of the particles is significantly determined by their velocity and temperature. Particle velocity correlates with the amount of kinetic energy that is converted to plastic deformation and thermal heating. The initial particle temperature significantly influences the mechanical properties of the particle. Velocity and temperature of the particles have nonlinear dependence on the pressure and temperature of the gas at the nozzle entrance. In this contribution, a simulation model based on the reactingParcelFoam solver of OpenFOAM is presented and applied for an analysis of particle velocity and temperature in the cold spray nozzle. The model combines a compressible description of the gas flow in the nozzle with a Lagrangian particle tracking. The predictions of the simulation model are verified based on an analytical description of the gas flow, the particle acceleration and heating in the nozzle. Based on experimental data, the drag model according to Plessis and Masliyah is identified to be best suited for OpenFOAM modeling particle heating and acceleration in cold spraying.
This article is an invited paper selected from presentations at the 2017 International Thermal Spray Conference, held June 7-9, 2017, in Du¨sseldorf, Germany, that has been expanded from the original presentation. & K.-H. Leitz [email protected] 1
Plansee SE, Metallwerk-Plansee-Straße 71, 6600 Reutte, Austria
Keywords analytical model cold spray computational fluid dynamics particle temperature particle trajectories particle velocity process modeling
Cold Spraying: Technology Principle and Challenges In cold spraying, a powder coating material is accelerated in the gas flow of a supersonic nozzle to velocities of up to 1000 m/s. Additionally the particles are heated by the gas. When the powder hits a substrate to be coated, the kinetic energy of the particles is converted to plastic deformation work. It is generally assumed that the particle adheres to the substrate when thermal softening at the contact interface overcomes strain and strain rate hardening. The velocity at which this occurs is called ‘‘critical velocity.’’ Figure 1 shows the principle of cold spraying. More detailed descriptions of the cold spray technology can be found in Ref 1-6. Velocity and temperature of the particles in cold spraying are indirectly controlled by the pressure and the temperature of the process gas at the entrance of the nozzle. Whereas there exist various approaches for an experimental measurement of the particle
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