Simplified model for droplet combustion in a slow convective flow

Ackerman, M.; Williams, Forman A.

doi:10.1016/j.combustflame.2005.08.025

Cited by 11 publications

(5 citation statements)

References 12 publications

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“…It is noted that the droplet-gas relative velocity and the presence of a support fiber can have an appreciable influence on droplet burning rates [15][16][17]. In the present experiments, the use of a thin tethering fiber and a symmetric ignition system kept droplet velocities very small, for example, 1 mm/s or less, as measured from the droplet-view camera.…”

Section: Resultsmentioning

confidence: 65%

Combustion of Submillimeter Heptane/Methanol and Heptane/Ethanol Droplets in Reduced Gravity

Aharon

Tam

Shaw

2013

Journal of Combustion

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Reduced-gravity experiments were performed on combustion of droplets composed of n-heptane mixed with methanol or ethanol. The initial alcohol mass fraction in a droplet was 0% (pure heptane) or 5%. The experiments were performed at 0.1 MPa and 25°C with air or with ambients of oxygen and helium with oxygen mole fractions of 0.3 or 0.4. Initial droplet diameters were in the range 0.67 mm to 0.92 mm. After considering measurement uncertainties, burning rates decreased appreciably as the initial droplet diameter increased for combustion in air but not for combustion in the oxygen/helium environments. It was also found that addition of either methanol or ethanol did not influence burning rates appreciably and that burning rates were larger for the oxygen/helium environments than for air if initial droplet diameter dependences were accounted for.

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Section: Resultsmentioning

confidence: 65%

Combustion of Submillimeter Heptane/Methanol and Heptane/Ethanol Droplets in Reduced Gravity

Aharon

Tam

Shaw

2013

Journal of Combustion

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“…Indeed, engineering power generation combustion systems operate at elevated ambient pressure and temperature conditions coupled with forced convective (laminar or/and turbulent) flow. The effect of forced flow/convection on hydrocarbon droplet combustion has been studied quite extensively under laminar flow conditions and therefore there is a wealth of knowledge (see, e.g., recent references [1][2][3][4][5][6][7][8][9][10], and references cited therein, M. Birouk ( ) · S. L. Toth Department of Mechanical Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada e-mail: madjid.birouk@umanitoba.ca to cite only a few). However, studies reporting on the effect of a turbulent or an acoustic field are quite limited (e.g., [11][12][13][14][15][16][17]).…”

Section: Introductionmentioning

confidence: 99%

Hydrocarbon Droplet Turbulent Combustion in an Elevated Pressure Environment

Birouk

Toth

2015

Flow Turbulence Combust

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New experimental data on the effect of turbulence on the combustion of nheptane and n-decane droplet at elevated pressure are reported. Turbulent flow field in the central volume of a spherical vessel was generated by a set of eight axial fans. Flow characterization demonstrated that turbulence is isotropic and homogeneous within the 40 mm central volume of the vessel. The combustion of n-heptane and n-decane droplet was examined by varying turbulence intensity via the fans rotational speed and ambient pressure and temperature inside the vessel/chamber. Results showed that droplet burning rate becomes sensitive to turbulence only at elevated ambient pressure. Droplet flame extinction was found to depend on the heat loss from the droplet envelop flame, which increases with turbulence intensity.

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“…There are prior analytical studies of droplet vaporization (including combustion) and motion in Stokes flow, e.g. Gogos & Ayyaswamy (1988), Jog, Ayyaswamy & Cohen (1996) and Ackerman & Williams (2005), but these studies did not consider the influences of thermocapillary stresses. Subramanian, Zhang & Balasubramaniam (1999) analysed mass transport from a droplet executing thermocapillary motion, but where the thermocapillary motion was driven by a temperature gradient that was imposed in the far field.…”

Section: Introductionmentioning

confidence: 99%

Influence of the gas-phase Lewis number and thermocapillary stress on motion of a slowly evaporating droplet in Stokes flow

Shaw

2022

J. Fluid Mech.

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The influence of thermocapillary stresses on motion of a slowly evaporating single-component droplet in Stokes flow is investigated analytically for the situation where the environment does not have a temperature gradient in the far field. The conservation equations are solved in the liquid and gas phases and coupled at the gas–liquid interface by applying conditions for conservation of mass, species, momentum and energy. It is found that thermocapillary stresses may influence droplet motion by changing the the interface velocity, and that the gas-phase Lewis number of the evaporating component determines whether Marangoni effects increase or decrease droplet drag. If the Lewis number is less than unity, then thermal Marangoni effects increase droplet drag, while if the Lewis number is greater than unity, then thermal Marangoni effects decrease droplet drag. This is related to the sign of the temperature gradient along the droplet surface that is induced by convection. It is found that conditions may exist where a vaporizing droplet in a microgravity environment will exhibit continuous translational motion driven by thermocapillary effects.

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Simplified model for droplet combustion in a slow convective flow

Cited by 11 publications

References 12 publications

Combustion of Submillimeter Heptane/Methanol and Heptane/Ethanol Droplets in Reduced Gravity

Combustion of Submillimeter Heptane/Methanol and Heptane/Ethanol Droplets in Reduced Gravity

Hydrocarbon Droplet Turbulent Combustion in an Elevated Pressure Environment

Influence of the gas-phase Lewis number and thermocapillary stress on motion of a slowly evaporating droplet in Stokes flow

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