Experimental Study of Coaxial Atomizers Scaling. Part I: Dense Core Zone

Leroux, B.; Delabroy, Olivier; Lacas, F.

doi:10.1615/atomizspr.v17.i5.10

Cited by 48 publications

(42 citation statements)

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“…Engelbert et al [26] reported an exponent of -0.3 for the same atomiser. Leroux et al [29] reported a value of the power law exponent of -0.3 for their airblast atomiser when scaling to the air to liquid momentum flux ratio which is also comparable with the exponent found here, as in our case the area ratio was constant for all measurements and the value of the exponent would be the same if scaling was according to the momentum flux ratio. It is possible that despite the difference in the absolute value of the breakup length between the two techniques that the exact location of the breakup point is not critical to establishing the correlation of the breakup length to the momentum ratio.…”

Section: Resultssupporting

confidence: 90%

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Structure of the Continuous Liquid Jet Core during Coaxial Air-Blast Atomisation

Charalampous

Hardalupas

Taylor

2009

International Journal of Spray and Combustion Dynamics

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This paper investigates the structure of the continuous liquid jet of a coaxial air-blast atomiser over a range of Weber numbers 60-1040, Reynolds numbers of liquid jet 5400-21700 and air to liquid momentum ratios of the two streams of 1.7-335. A novel optical technique, based on internal illumination of the liquid jet through the jet nozzle by a laser pulse, which excites a fluorescing dye introduced in the atomizing liquid, was used to obtain instantaneous measurements of the breakup length and the three dimensional location of the liquid core of the continuous liquid jet. The latter was achieved by simultaneously imaging the liquid jet from two directions normal to each other. Such measurements are usually prevented by droplets surrounding the liquid jet at the dense spray near the nozzle exit. The measurements showed that the break-up length of the liquid jet scaled well with the air to liquid momentum ratio. The standard deviation of the temporal fluctuations of the break-up length was around 10% of the mean breakup length for each considered flow condition. The instantaneous jet surface does not develop axi-symmetric wave structures but the time-averaged liquid jet is axi-symmetric around the nozzle axis, while the maximum deflection of the liquid jet occurs close to the breaking point.

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Section: Resultssupporting

confidence: 90%

“…Scaling based on the momentum flux ratio (which is different from the momentum ratio of Eq. (3) since the area ratio of the two streams is omitted) has also been used [29]. The flowrates for each flow condition and their corresponding We, Re L and MR are summarized in Table 1.…”

Section: Figurementioning

confidence: 99%

Structure of the Continuous Liquid Jet Core during Coaxial Air-Blast Atomisation

Charalampous

Hardalupas

Taylor

2009

International Journal of Spray and Combustion Dynamics

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“…They also determined a critical value of M (order of 35) at which the liquid (water) cone is chopped off and the superpulsating mode is reached. Leroux et al [202] observed the Rayleigh-type breakup regime for 7 10 / . and the superpulsating sub-mode for 2 10 / .…”

Section: Coaxial Jetsmentioning

confidence: 98%

“…Leroux et al [202] Hardalupas et al [205] found that LC for the pulsating and superpulsating modes of the fiber-type regime is proportional to 1 . and the proportionality coefficient is a function of DG and DL with a greater dependence on the latter.…”

Section: Coaxial Jetsmentioning

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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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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“…In these atomization studies, the gas Weber number (We), the Reynolds number (Re), and the momentum flux ratio (M) have been considered as the crucial parameters with respect to atomizing the liquid jet. These three parameters can be defined by the following equations [7,15]:…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Atomization and Chemiluminescence Characteristics of Ethanol Flame

Zhang

Song

Guo

et al. 2017

Journal of Spectroscopy

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The breakup regime in ethanol diffusion flame under different conditions was studied by the high speed camera system combined with the UV camera system. Spray angle and Weber number (We) were used to represent the change of breakup regime. With the increases of spray angle and We, the breakup mode changes from the Rayleigh-type breakup regime to the superpulsating regime. The reaction area and intensity of ethanol flames under different breakup regimes could be discussed by theOH⁎distribution. From Rayleigh-type breakup regime to superpulsating breakup regime, theOH⁎distribution increased and the oxidation-reduction reaction area expanded. At the condition of superpulsating breakup mode, the intensity ofOH⁎was significantly higher than that of other modes. The flame luminous length can be obtained by theOH⁎emission, andOH⁎distribution reflects the structure of flame. When the breakup regime changes from the fiber-type breakup regime to the superpulsating regime, the flame luminous length increases suddenly.

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Experimental Study of Coaxial Atomizers Scaling. Part I: Dense Core Zone

Cited by 48 publications

References 0 publications

Structure of the Continuous Liquid Jet Core during Coaxial Air-Blast Atomisation

Structure of the Continuous Liquid Jet Core during Coaxial Air-Blast Atomisation

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

Experimental Study on the Atomization and Chemiluminescence Characteristics of Ethanol Flame

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