Experimental Study of Coaxial Atomizers Scaling. Part Ii: Diluted Zone

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

doi:10.1615/atomizspr.v17.i5.20

Cited by 15 publications

(17 citation statements)

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“…The effect of M on bag‐type breakup and superpulsating breakup is huge. In the condition of

GLR \to \infty

A_{normall} / A_{normalg} \to 0

, when M is very big ( M > 20), it is the superpulsating breakup. When M is medial (0.08 < M < 20), there are four atomization regimes, which are Rayleigh‐type breakup, bag‐type breakup, membrane‐fiber breakup, and fiber‐type breakup.…”

Section: Resultsmentioning

confidence: 92%

“…L / D values calculated using this correlation are plotted against the measured values in Figure . The correlation of Leroux et al on the characteristic length L is

\frac{L}{D} = 10 M^{- 0.3}

…”

Section: Resultsmentioning

confidence: 96%

“…In the experiment of Leroux et al, the range of

{true(\frac{A_{normall}}{A_{normalg}} true)}^{- 0.17}

is 1.0–2.8, so the average of

{true(\frac{A_{normall}}{A_{normalg}} true)}^{- 0.17}

is about 1.9. Then, based on Eq.…”

Section: Resultsmentioning

confidence: 99%

“…In We–Re map, the parameter of air exit diameter D o is neglected. In M –

R e_{g}^{}

map, the parameter of water exit diameter D is neglected. So these criterions in the literature can not reflect the impact of nozzle size and should be modified.…”

Section: Resultsmentioning

confidence: 99%

“…So the We–Re map needs to be improved. Subsequently, Leroux et al investigate the behavior of coaxial liquid jets produced by nine different atomizers. They suggest categorizing the primary breakup mechanism in a M–

R e_{normalg}^{}

map, where M is the momentum flux ratio

M = ρ_{normalg} u_{normalg}^{2} / (ρ_{normall} u_{normall}^{2})

and

R e_{normalg}^{}

is the gas Reynolds number

R e_{normalg}^{} = ρ_{normalg} D_{normalo} u_{normalg} / μ_{normalg}

, where

μ_{normalg}

is the dynamic viscosity of gas.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Influence of atomizer exit area ratio on the breakup morphology of coaxial air and round water jets

et al. 2014

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The goal of this article is to study the effect of atomizer exit area ratio on atomizer performance. The experiments are performed on the round liquid jet breakup of seven coaxial air‐blast atomizers with water–air systems. The breakup morphology of liquid jet is observed first. The membrane‐type breakup can be divided into two subregimes called bag‐type breakup and membrane‐fiber breakup, and a correlation of characteristic length on bag‐type breakup regime is obtained. Then, we analyze the influence of atomizer exit area ratio on the breakup morphology of water‐air jets. To obtain reasonable atomization morphology criterions, the atomizer exit area ratio is used to modify the Weber number and momentum flux ratio per unit volume. This method is found to be able to explain different experimental results in the literature, which is also close to the results of round liquid jet in cross air flow and secondary atomization. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2335–2345, 2014

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“…The effect of M on bag‐type breakup and superpulsating breakup is huge. In the condition of

GLR \to \infty

A_{normall} / A_{normalg} \to 0

Section: Resultsmentioning

confidence: 92%

“…L / D values calculated using this correlation are plotted against the measured values in Figure . The correlation of Leroux et al on the characteristic length L is

\frac{L}{D} = 10 M^{- 0.3}

…”

Section: Resultsmentioning

confidence: 96%

“…In the experiment of Leroux et al, the range of

{true(\frac{A_{normall}}{A_{normalg}} true)}^{- 0.17}

is 1.0–2.8, so the average of

{true(\frac{A_{normall}}{A_{normalg}} true)}^{- 0.17}

is about 1.9. Then, based on Eq.…”

Section: Resultsmentioning

confidence: 99%

“…In We–Re map, the parameter of air exit diameter D o is neglected. In M –

R e_{g}^{}

map, the parameter of water exit diameter D is neglected. So these criterions in the literature can not reflect the impact of nozzle size and should be modified.…”

Section: Resultsmentioning

confidence: 99%

R e_{normalg}^{}

map, where M is the momentum flux ratio

M = ρ_{normalg} u_{normalg}^{2} / (ρ_{normall} u_{normall}^{2})

and

R e_{normalg}^{}

is the gas Reynolds number

R e_{normalg}^{} = ρ_{normalg} D_{normalo} u_{normalg} / μ_{normalg}

, where

μ_{normalg}

is the dynamic viscosity of gas.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Influence of atomizer exit area ratio on the breakup morphology of coaxial air and round water jets

et al. 2014

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Influence of nozzle geometry on primary and large-scale instabilities in coaxial injectors

Kumar

Sahu

2020

Chemical Engineering Science

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Autoignition of an n-heptane jet in a confined turbulent hot coflow of air

Gupta

Markides

2020

Experimental Thermal and Fluid Science

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The autoignition of a continuous, single jet of pure liquid n-heptane injected concentrically and axisymmetrically from a water-cooled circular nozzle into a confined turbulent hot coflow (CTHC) of air at atmospheric pressure has been investigated experimentally at air temperatures up to 1150 K and velocities up to 40 m/s. The aim of this work was to examine the emergence of liquid-fuel autoignition in the presence of flow, mixture and phase inhomogeneities, to which end, the velocity, temperature and fuel-droplet fields inside the CTHC reactor were characterized in a series of dedicated measurement campaigns. Distinct phenomena were identified concerning the emergence of various regimes: no autoignition, random spots, and continuous flame. In the random spots regime, autoignition appeared in the form of well-defined, discrete localized spots occurring randomly within the reactor, similar to observations in a similar apparatus with gaseous fuels [1][2][3][4]. High-speed optical measurements of these random spots were made from which the autoignition locations/lengths were measured, and then used to infer average autoignition delay, or residence, times from injection based on the bulk air velocity. An increase in the air temperature moved the region of autoigniting spots closer to the injector nozzle, thus decreasing the autoignition length and also decreasing the autoignition delay time. Generally, autoignition moved downstream with increasing bulk air velocity, but the delay times decreased contrary to the aforementioned earlier work with pre-vaporized n-heptane in this geometry.Of interest is the finding that at the highest investigated air velocities, the autoignition length decreased as the air velocity increased, which again deviates from the same earlier work with vaporized n-heptane. Furthermore, higher liquid injection velocities also resulted in increased autoignition lengths and times.The results from this work suggest that the turbulent inhomogeneous autoignition of liquid fuels cannot be directly predicted from chemical delay times of equivalent homogeneous systems, or even from knowledge of the turbulent inhomogeneous autoignition of single-phase (gaseous) fuels in the same reactor system (flow geometry, fuel, conditions, etc.), and that the effects of evaporation and turbulent mixing must be accounted for. The data can assist the development of advanced turbulent and multiphase reacting flow models.

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Experimental Study of Coaxial Atomizers Scaling. Part Ii: Diluted Zone

Cited by 15 publications

References 0 publications

Influence of atomizer exit area ratio on the breakup morphology of coaxial air and round water jets

Influence of atomizer exit area ratio on the breakup morphology of coaxial air and round water jets

Influence of nozzle geometry on primary and large-scale instabilities in coaxial injectors

Autoignition of an n-heptane jet in a confined turbulent hot coflow of air

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