A new nozzle design for dc plasma spray guns

Jankovic, M.; Mostaghimi, J.

doi:10.1007/bf01447063

Cited by 17 publications

(9 citation statements)

References 20 publications

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“…2. The performance of a conventional conical shroud is not satisfactory due to the entrainment of air at the exit region [11]. The new design is based on a modification of the conventional shape by optimizing the profile of nozzle to a conical shape with a straight rear end.…”

Section: Shroud Designmentioning

confidence: 99%

“…Shrouded plasma spray can be considered as a useful technology to produce low oxygen containing titanium coatings. This is to modify plasma spray torches by using an attachment onto an atmospheric plasma spraying torch [11][12][13][14]. In this work, plasma spraying of titanium has been carried out by using a shroud in order to shield molten particles from reacting with surrounding environment.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure and Phase Composition of Titanium Coatings Plasma Sprayed with a Shroud

Zhou

Luo

2018

MATEC Web Conf.

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Abstract. Excellent corrosion resistance has made titanium a preferred material for use in industry with harsh environments. Protective titanium coatings combined with cheap bulk materials are expected to enable sufficient corrosion protection and lower the cost. Plasma spray processing of titanium feedstock becomes a challenging topic of research as titanium powder particles have to experience high temperatures in the flight during the thermal spraying process in an open air environment. In this paper, plasma spraying of titanium has been carried out by using a shroud in order to shield molten particles from reacting with surrounding environment. Microstructure analyses on the titanium coatings were performed by using SEM, EDS and XRD. The results show that the shroud attachment is capable of withstanding high plasma temperatures; the as-sprayed shrouded titanium coating exhibits a similar phase composition as the pure titanium powder, and an enhanced microstructure with a lower porosity for the titanium coating plasma-sprayed with a shrouding system is observed.

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Section: Shroud Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microstructure and Phase Composition of Titanium Coatings Plasma Sprayed with a Shroud

Zhou

Luo

2018

MATEC Web Conf.

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“…During past decades, major progress has been achieved by designing nozzle contours to produce controlled expansion plasma flow, and many experiments have been done to investigate the plasma jet characteristics produced by torches with different anode configurations. (11)(12)(13)(14) However, most research work were done to improve plasma spraying techniques experimentally, by analyzing the ejected plasma jet, and the characteristic of plasma flow inside the plasma torch was seldom studied by now.…”

Section: Introductionmentioning

confidence: 98%

Comparative Study of Flow Characteristics Inside Plasma Torch with Different Nozzle Configurations

Yuan

Zhao

et al. 2004

Plasma Chem Plasma Process

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A numerical analysis of the influence of different nozzle configurations on the plasma flow characteristics inside D.C plasma torches is presented to provide an advanced nozzle design basis for plasma spraying torches. The assumption of steady-state, axis-symmetric, local thermodynamic equilibrium, and optically thin plasma is adopted in a two-dimensional modeling of plasma flow inside the plasma torch. The PHOENICS software is used for solving the governing equations, i.e. the conservation equations of mass, momentum, and energy along with the equations describing the K-epsilon model of turbulence. The calculated arc voltages are consistent with the experimental results when arc current, gas inflow rate, and working gas are the same as the experimental parameters. Temperature, axial velocity contours inside plasma torches, profiles along the torch axis and profiles at the outlet section are presented to show the plasma flow characteristics. Comparisons are made among those torches. The results show that torches with different anode nozzle configurations produce different characteristics of plasma flows, which suggest some important ideas for the advanced nozzle design for plasma spraying. In order to validate the model and to show its level of predictivity, a comparison of the model with experimental results encountered in the literature is presented in the last part.

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“…A variety of diagnostic techniques have been employed to study the entrainment of ambient gas into the turbulent plasma jet, and many measured results have also been reported concerning the evolution of plasma parameters in plasma jets [5,6,9,10,[14][15][16]. The modeling results reported in [19][20][21] showed that since turbulent transport mechanism is dominant in the turbulent plasma jet, the mass flow rate of the ambient air entrained into the turbulent plasma jet is comparatively large (e.g.…”

Section: Introductionmentioning

confidence: 99%

Direct Measurement of the Gas Entrainment Into a Turbulent Thermal Plasma Jet

Wang

Wei

Meng

et al. 2010

Plasma Chem Plasma Process

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An experimental study is conducted to investigate the entrainment characteristics of a turbulent thermal plasma jet issuing from a DC arc plasma torch operating at atmospheric pressure. The mass flow rate of the ambient gas entrained into the turbulent plasma jet is directly measured by use of the so-called ''porous-wall chamber'' technique. It is shown that a large amount of ambient gas is entrained into the turbulent plasma jet. With the increase of the gas mass flow rate at the plasma jet inlet or the plasma torch exit, the mass flow rate of entrained ambient gas almost linearly increases but its ratio to the jetinlet mass flow rate decreases. The mass flow rate of the entrained gas increases with the increase of the arc current or jet length. It is also found that using different ways to inject the plasma-forming gas into the plasma torch affects the entrainment rate of the turbulent plasma jet. The entrainment rate expression established previously by Ricou and Spalding (J. Fluid Mech. 11: 21, 1961) for the turbulent isothermal jets has been used to correlate the experimental data of the entrainment rates of the turbulent thermal plasma jet, and the entrainment coefficient in the entrainment rate expression is found to be in range from 0.40 to 0.47 for the turbulent thermal plasma jet under study.

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A new nozzle design for dc plasma spray guns

Cited by 17 publications

References 20 publications

Microstructure and Phase Composition of Titanium Coatings Plasma Sprayed with a Shroud

Microstructure and Phase Composition of Titanium Coatings Plasma Sprayed with a Shroud

Comparative Study of Flow Characteristics Inside Plasma Torch with Different Nozzle Configurations

Direct Measurement of the Gas Entrainment Into a Turbulent Thermal Plasma Jet

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