Three-Dimensional Simulation of Thermal Plasma Spraying of Partially Molten Ceramic Agglomerates

Ahmed, Ikram; Bergman, T. L.

doi:10.1361/105996300770349953

Cited by 51 publications

(21 citation statements)

References 8 publications

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“…In this model, the instantaneous value of fluctuating gas flow velocity was used and assumed to be isotropic and obey the Gaussian probability distribution [10,20] so that;…”

Section: Stochastic Trackingmentioning

confidence: 99%

“…Many workers [9][10][11][12] have investigated and showed that for typical plasma jet injection conditions, many operating parameters affecting heat, momentum and mass transfers between the plasma jet and the entrained particles. However, most of these efforts were conducted with the exclusion of substrate in the computational fluid dynamics (CFD) models for the sake of idealization simplicity [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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Comparative Study of Plasma Spray Flow Fields and Particle Behavior Near to Flat Inclined Substrates

Kang

2006

Plasma Chem Plasma Process

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Numerical models have been developed using computational fluid dynamics (CFD) analysis program FLUENT V6.02 © to investigate the effect of the substrate on the behavior of the plasma flow fields and in-flight particles. Simulations are performed for cases where flat substrates are either present or absent, for the former, the substrate is oriented perpendicularly or inclined to the torch axis. It is shown that although the presence of perpendicular or inclined substrate significantly influences the plasma flow fields at the vicinity of the substrate, the particle behavior remain relatively unaffected. The insignificant effect of the substrate on particle behavior is qualitatively verified by experimental observation using SprayWatch © imaging diagnostics equipment. Images captured by the equipment confirm that the particles travel through the plasma plume with high momentum and show no sudden change in their trajectories right before impacting the substrate. Both the numerical and experimental findings show that the freestream model is sufficiently detailed for future work of this nature.Keywords Atmospheric plasma spray · CFD modeling · Particle behavior · Inclined substrate Nomenclature ACross section area (m 2 ) BEmpirical constant (= 9.81) C D Drag coefficient C µ Empirical constant (= 0.09) C 1ε Empirical constant (= 1.44) C 2ε Empirical constant (= 1.92) C p Specific heat capacity (J/kg K) D Diffusion coefficient (m 2 /s)

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“…In this model, the instantaneous value of fluctuating gas flow velocity was used and assumed to be isotropic and obey the Gaussian probability distribution [10,20] so that;…”

Section: Stochastic Trackingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparative Study of Plasma Spray Flow Fields and Particle Behavior Near to Flat Inclined Substrates

Kang

2006

Plasma Chem Plasma Process

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“…The first droplets, containing solid particles, fragment from the suspension jet and remain in the plasma fringe, whereas the jet continues its trajectory toward the plasma core ( Ref 17). Since the plasma jet is characterized by sharp thermal and kinetic radial gradients ( Ref 18,19), this leads to an inhomogeneous treatment of particles along their trajectories. The solid particles that penetrated into the plasma core will impact upon the substrate in a molten state and form splats, whereas those traveling in the plasma fringes of lower temperature will remain untreated and form angular embedded particles.…”

Section: Introductionmentioning

confidence: 99%

Suspension Plasma-Sprayed Alumina Coating Structures: Operating Parameters Versus Coating Architecture

et al. 2008

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International audienceSuspension plasma spraying (SPS) is able to process sub-micrometric-sized feedstock particles and permits the deposition of layers thinner (from 5 to 50 lm) than those resulting from conventional atmospheric plasma spraying (APS). SPS consists in mechanically injecting within the plasma flow a liquid suspension of particles of average diameter varying between 0.02 and 1 lm, average values. Upon penetration within the DC plasma jet, two phenomena occur sequentially: droplet fragmentation and evaporation. Particles are then processed by the plasma flow prior their impact, spreading and solidification upon the surface to be covered. Depending upon the selection of operating parameters, among which plasma power parameters (operating mode, enthalpy, spray distance, etc.), suspension properties (particle size distribution, powder mass percentage, viscosity, etc.), and substrate characteristics (topology, temperature, etc.), different coating architectures can be manufactured, from dense to porous layers. Nevertheless, the coupling between the parameters controlling the coating microstructure and properties are not yet fully identified. The aim of this study is to further understand the influence of parameters controlling the manufacturing mechanisms of SPS alumina coatings, particularly the spray beads influence

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“…[38][39][40][41][42][43] Most of them adopt 2-D geometry and steady state and use practically the same methodology for the calculation of the turbulent plasma jet and particle behavior. The most advanced models deal with 3-D geometry, multiple particle injection and time-dependent phenomena such as the arc fluctuation and its effect on particle treatment in the jet and coating building on the substrate.…”

Section: Introductionmentioning

confidence: 99%

Direct Current Plasma Spraying: Diagnostics and Process Simulation

et al. 2006

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This paper presents our current knowledge in direct current (d.c.) plasma spraying with conventional stick‐type cathode plasma torches. It deals with the experimental methods and models used to better understand and /or control the characteristics of plasma jet, particles in‐flight and at impact. The first part refers to measurements and on‐line monitoring or control. The emphasis is on (i) the effect of arc root fluctuations and electrode wear on particle treatment and coating formation; (ii) the drastic importance of the interface between the flattening particles and substrate. The second part examines the models used to predict gas flow field and particle parameter distributions at impact. It presents: (i) steady and 2‐D models that allow optimal experimental design with a limited number of experiments as well as education and training; (ii) 3‐D and time dependent models that make it possible to take account of the arc root fluctuation at the anode and a stochastic and time‐dependent particle injection description.

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Three-Dimensional Simulation of Thermal Plasma Spraying of Partially Molten Ceramic Agglomerates

Cited by 51 publications

References 8 publications

Comparative Study of Plasma Spray Flow Fields and Particle Behavior Near to Flat Inclined Substrates

Comparative Study of Plasma Spray Flow Fields and Particle Behavior Near to Flat Inclined Substrates

Suspension Plasma-Sprayed Alumina Coating Structures: Operating Parameters Versus Coating Architecture

Direct Current Plasma Spraying: Diagnostics and Process Simulation

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