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Ang, C.B.; Ng, H. W.; Yu, S. C. M.; Lam, Yee Cheong

doi:10.1023/a:1007040227158

Cited by 13 publications

(5 citation statements)

References 11 publications

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“…Torch efficiency, η, which takes into account for the heat loss mainly through cooling water in plasma torch was assumed to be 67% after [18].…”

Section: Governing Equationsmentioning

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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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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“…Torch efficiency, η, which takes into account for the heat loss mainly through cooling water in plasma torch was assumed to be 67% after [18].…”

Section: Governing Equationsmentioning

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 plasma gun efficiency is at 67% (Ang et al (11) ). The geometrical sketch of SG-100 plasma gun is illustrated in Fig.…”

Section: Experimental Set-upmentioning

confidence: 99%

“…As described previously by Ref. 11, the preferred distance between the nozzle and substrate should be at about 100 mm, thus the crosssectional planes measurements were set at 50, 80, 100 and 120 mm, respectively, so as to cover the entire practical distance. On each cross-sectional plane, measurements points were ranged from 77 to 144 depending on the area of the spraying.…”

Section: Experimental Set-upmentioning

confidence: 99%

The Particle In-Flight Characteristics in Plasma Spraying Process Measured by Phase Doppler Anemometry (PDA)

Ma¹,

Yu²,

Ng³

2005

Plasma Chem Plasma Process

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Detailed measurements of particle in-flight characteristics have been carried out using a PDA system for benchmarking as well as to provide further information to aid the development of simulation models. The parameters studied included four conditions of primary gas flow rate and carrier gas flow rate. The particle velocities, diameters, and the corresponding volume flux at different locations were obtained. Due to the one port particle injection arrangement, it was noted that particles in general sprayed with an angle (η), deviated from the nozzle axis Z n , to the opposite side of the powder feeder port. The particles would also deviate from the spraying cone axis with a divergence angle (φ). The deviation and divergence angles were examined under different plasma spraying conditions. The measurement data rates at different cross-sectional planes were also obtained so as to compare the results derived from the volume flux measurement and the actual coating on a substrate at the equivalent standoff distance. It was found that the spraying area obtained from the measurement-data-rate increased with downstream distance and a linear relationship between spraying area and distance was also established. Comparing the integrated results, it was noted that the spraying areas derived from the measurement data rate were close to the actual spraying areas obtained from the coordinate measurement machine (CMM) results.

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“…However in the process numerous particles are simultaneously injected (for example about 10 8 s -1 for alumina particles 20µm in diameter, with a flow rate of 3 kg/h). Thus the three following problems have to be accounted for [13,[14][15][16][17][18][19][20][21] :…”

Section: Introductionmentioning

confidence: 99%

Fast modelling of plasma jet and particle behaviours in spray conditions

et al. 2005

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International audienceThis paper presents a simplified code allowing to find in a few minutes the trends of the d.c. plasma spray process, at least for a single particle in flight. It is based on a parabolic two dimension (2D) flow for the plasma jet and a three dimension (3D) calculation for the heat and momentum transfer to a single particle. It neglects the carrier gas flow rate- plasma flow interaction but the obtained trends are in good agreement with those obtained with 3D sophisticated codes. However results depend strongly on the turbulence model, the plasma effect corrections chosen for the heat and momentum transfer. Thus, as with 3D codes, the model has to be backed by experiments. It can be used to train operators and let them “see” almost immediately the effects of the different macroscopic spray parameters. The code and the plasma properties used can be freely downloaded

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Cited by 13 publications

References 11 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

The Particle In-Flight Characteristics in Plasma Spraying Process Measured by Phase Doppler Anemometry (PDA)

Fast modelling of plasma jet and particle behaviours in spray conditions

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