Extinction of a free methanol droplet in microgravity

Cho, S.Y.; Choi, Mijin; Dryer, Frederick L.

doi:10.1016/s0082-0784(06)80433-9

Cited by 41 publications

(21 citation statements)

References 6 publications

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“…The extinction point is characterized by a change of slope indicating the abruptness of the extinction phenomenon, although a small amount of vaporization from residual heat in the droplet and gas-phase continues even after extinction, as previously remarked by Cho et al [18]. The location where the diameter slope changes coincides with the end of visible flame chemiluminescence.…”

Section: S Russo and A Gomezsupporting

confidence: 63%

The extinction behavior of small interacting droplets in cross-flow

Russo¹,

Gomez²

2002

Combustion and Flame

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Experiments were conducted on monodisperse streams of small (Ͻ100 m) methanol and ethanol droplets, injected perpendicularly to the axis of an axisymmetric methane diffusion flame. After crossing the methane flame, the droplets ignited and continued to burn outside of the "domain of influence" of the gaseous flame till they eventually extinguished. The extinction behavior was studied as a function of droplet spacing, oxidizer concentration and velocity, and droplet velocity by measuring droplet size and velocity at the time of extinction using a commercial Phase Doppler Anemometer. The onset of droplet interaction effects on extinction was found at interdroplet distances well above the limits reported in the literature. The interaction is attributed to the vitiated atmosphere left behind by the leading droplet that affects the extinction conditions of the trailing one. The ratio between interdroplet time and convection time normal to the droplet direction of travel was found to be the controlling parameter. Results were correlated in terms of a critical Damköhler number that was found to scale as dY o,ϱ no /v, where d is the droplet diameter, Y o,ϱ is the oxidizer mass fraction, v is the droplet velocity, and n o is 0.5 and 0.75 for methanol and ethanol, respectively.

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Section: S Russo and A Gomezsupporting

confidence: 63%

The extinction behavior of small interacting droplets in cross-flow

Russo¹,

Gomez²

2002

Combustion and Flame

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show abstract

“…Most of the experimental researches deal with the fuel ethanol 1, 2, 3, 4, 5 and n-heptane 6,7,8,2,9 . Numerical simulations have been presented for methanol droplets 10 and n-heptane droplets 11,12,13,14 . Only a little number of studies do not assume spherical symmetry and nevertheless consider the physics of the droplets and the chemical processes in detail.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Droplet Combustion in a Cylindrical Furnace

Mondal

Roy

2010

J Chem Engg

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“…Especially, a detailed understanding of the basic physical and chemical processes, such as vaporization, transport, and chemical kinetics, and their interaction is of interest. The ignition or combustion of single droplets in a quiescent atmosphere has been investigated in detail both experimentally and numerically for different fuels, e.g., methanol [1][2][3] and n-heptane [4][5][6][7][8][9][10][11][12][13][14][15], by a large number of research groups. However, in all technical applications, fuel droplets are exposed to a convective environment and to accelerating or decelerating forces.…”

Section: Introductionmentioning

confidence: 99%

The ignition of methanol droplets in a laminar convective environment

Stauch

Maas

2008

Combustion and Flame

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Numerical simulations of the ignition of methanol droplets in a laminar convective environment are performed using detailed reaction mechanisms and detailed transport models. The flow velocities of the forced convection ranges from 0.01 up to 5 m/s, whereas the ambient gas temperature is varied between 1300 and 1500 K. The ignition delay time of a single droplet is found to decrease with increasing velocity of the convective gas flow. This decrease is attributed to the steepening of the spatial gradients of the profiles of physical variables, such as species mass fractions or temperature. This steepening is originated by a stronger gas flow and leads to a speed-up of the physical transport processes. For the studied flow conditions, an acceleration of the gas flow on the order of the gravitational acceleration does not show a significant influence on the ignition delay time. A downstream movement of the local ignition point with increasing flow velocity is observed. For higher flow velocities, an ignition in the wake of the droplet followed by an upstream flame propagation is found. After ignition, the formation of an envelope flame is detected. The structure of this envelope flame is studied.

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Extinction of a free methanol droplet in microgravity

Cited by 41 publications

References 6 publications

The extinction behavior of small interacting droplets in cross-flow

The extinction behavior of small interacting droplets in cross-flow

Numerical Analysis of Droplet Combustion in a Cylindrical Furnace

The ignition of methanol droplets in a laminar convective environment

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