Effect of the Increase in the Entrance Convergent Section Length of the Gun Nozzle on the High-Velocity Oxygen Fuel and Cold Spray Process

Sakaki, Kazuhiko; Shimizu, Yasuo

doi:10.1361/105996301770349268

Cited by 61 publications

(26 citation statements)

References 3 publications

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“…Sakaki and Shimizu [97] showed that as the convergent part length increased, the degree of particle melting increased; however, the particle velocity decreased slightly. In addition, the deposition efficiency and cross-sectional hardness of Al2O3-40 mass% TiO2 coatings grew as the convergent part length of the nozzle increased.…”

Section: Nozzle Shapementioning

confidence: 99%

See 1 more Smart Citation

A Comprehensive Review on Fluid Dynamics and Transport of Suspension/Liquid Droplets and Particles in High-Velocity Oxygen-Fuel (HVOF) Thermal Spray

2015

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Abstract:In thermal spraying processes, molten, semi-molten, or solid particles, which are sufficiently fast in a stream of gas, are deposited on a substrate. These particles can plastically deform while impacting on the substrate, which results in the formation of well-adhered and dense coatings. Clearly, particles in flight conditions, such as velocity, trajectory, temperature, and melting state, have enormous influence on the coating properties and should be well understood to control and improve the coating quality. The focus of this study is on the high velocity oxygen fuel (HVOF) spraying and high velocity suspension flame spraying (HVSFS) techniques, which are widely used in academia and industry to generate different types of coatings. Extensive numerical and experimental studies were carried out and are still in progress to estimate the particle in-flight behavior in thermal spray processes. In this review paper, the fundamental phenomena involved in the mentioned thermal spray techniques, such as shock diamonds, combustion, primary atomization, secondary atomization, etc., are discussed comprehensively. In addition, the basic aspects and emerging trends in simulation of thermal spray processes are reviewed. The numerical approaches such as Eulerian-Lagrangian and volume of fluid along with their advantages and disadvantages are explained in detail. Furthermore, this article provides a detailed review on simulation studies published to date. OPEN ACCESSCoatings 2015, 5 577

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Section: Nozzle Shapementioning

confidence: 99%

“…The effect of the increase in length of the nozzle convergent part on the deposition efficiency, coating microstructure, and hardness was numerically and experimentally investigated by Sakaki and Shimizu [97]. The deposition efficiency is defined as [31] mass of particles deposited on a surface mass of particles fed to the nozzle…”

Section: Nozzle Shapementioning

confidence: 99%

A Comprehensive Review on Fluid Dynamics and Transport of Suspension/Liquid Droplets and Particles in High-Velocity Oxygen-Fuel (HVOF) Thermal Spray

2015

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“…First, the nozzle geometry is important either in the high-velocity oxygen-fuel (HVOF) thermal spray process or in the cold spray process. Sakaki and Shimizu [13] carried out numerical simulation and experiments to investigate the effect of the entrance geometry of the gun nozzle on the HVOF process, the study results also could be applied to the nozzle design for the cold spray method. The numerical and experimental research results for wedge-shaped supersonic nozzles, conducted by Alkhimov et al [14], showed that for a nozzle with particular dimensions for a given type of particles that produces the maximum possible particle velocity at the moment of impact on a target surface.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigations on cold gas dynamic spray process with nano- and microsize particles

Jen

Cui

et al. 2005

International Journal of Heat and Mass Transfer

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“…However, it has been addressed that the different meshing sizes in the FEA would lead to significantly different results, and appropriate meshing methods and boundary definition techniques are essentially required to achieve reliable outcomes ( . In contrast, with much more flexibility of the computation resources, simple one-dimensional isentropic flow models have been utilized to predict the particleÕs velocity for various cold spray conditions and nozzle designs ( Ref 13,17,[24][25][26][27]. The analytic solutions yielded from the isentropic assumptions agreed reasonably well with the experimental results and enabled insights into the cold spray process, but the neglect of friction in the 1D calculation introduced overestimation of the particle velocity and hence of the deposition efficiency ( Ref 26).…”

Section: Introductionmentioning

confidence: 99%

A One-Dimensional Flow Model with Adiabatic Friction for Rapid Estimation of Cold Spray Flow Conditions

Yin

Wang

2015

J Therm Spray Tech

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While commercially available computational fluid dynamic packages are employed nowadays to analyze the spraying behavior of the cold spray (CS) system and optimize the nozzle geometry design, using these packages is often prohibitive because of complex computational resource requirements and expensive copyright licenses. This paper proposes a quick and economical method for predicting the performance of the CS system, while asking for minimal computational resource. A one-dimensional adiabatic friction model with the consideration of friction was developed to calculate the critical pressure of nozzles under different expansion ratios and the gas/particle velocity at different spraying conditions. The accuracy of the critical pressure calculation was evidenced by polymeric nozzle destructive tests. The particle velocities achieved from the nozzles with different expansion ratios were measured and compared with the velocity values calculated by the model. The suggested adiabatic friction model is validated by the well-matched values between the calculated results and the experimental data.

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Effect of the Increase in the Entrance Convergent Section Length of the Gun Nozzle on the High-Velocity Oxygen Fuel and Cold Spray Process

Cited by 61 publications

References 3 publications

A Comprehensive Review on Fluid Dynamics and Transport of Suspension/Liquid Droplets and Particles in High-Velocity Oxygen-Fuel (HVOF) Thermal Spray

A Comprehensive Review on Fluid Dynamics and Transport of Suspension/Liquid Droplets and Particles in High-Velocity Oxygen-Fuel (HVOF) Thermal Spray

Numerical investigations on cold gas dynamic spray process with nano- and microsize particles

A One-Dimensional Flow Model with Adiabatic Friction for Rapid Estimation of Cold Spray Flow Conditions

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