Influence of oxygen concentration on the sooting behavior of ethanol droplet flames in microgravity conditions

Yozgatlıgil, Ahmet; Park, Seul-Hyun; Choi, Mijin; Kazakov, Andrei F.; Dryer, Frederick L.

doi:10.1016/j.proci.2006.08.087

Cited by 30 publications

(20 citation statements)

References 18 publications

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“…Because of the interest in puffing and micro-explosion, many researchers have studied these using single droplet experiments (Segawa, et al, 2000;Watanabe, et al, 2009;Watanabe, et al, 2010;Suzuki, et al, 2011;Mura, et al, 2014;Califano, © 2014 The Japan Society of Mechanical Engineers [DOI: 10.1299/jtst.2014jtst0009] et al, 2014). The fiber-support technique, used to anchor the droplet (Segawa, et al, 2000;Bae and Avedisian, 2004;Yozgatligil, et al, 2007;Watanabe, et al, 2009;Watanabe, et al, 2010;Suzuki, et al, 2011;Mura, et al, 2014;Califano, et al, 2014), has been used in studies of secondary atomization because it provides considerably useful information regarding, for example, clear droplet behavior. Because nucleation on the surface of the wire used in the fiber-support technique is unavoidable, some researchers have used unsupported techniques (Warnat, et al, 1994;Jackson and Avedisian, 1998;Mikami, et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

Observation of droplet behavior of emulsified fuel in secondary atomization in flame

Watanabe

Shoji

Yamagaki

et al. 2014

JTST

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The study aims to visualize droplet behaviors of emulsified fuel in secondary atomization in a flame stabilized in a laminar counterflow field. To study secondary atomization characteristics in the flame, direct photography of the flame using a color high-speed video camera (7,000 fps) and magnified shadow imaging of spray droplets using a monochrome high-speed video camera (180,064 fps) were used. Frequencies of secondary atomization in the flame were also discussed. As a result, "bright spots," which were of similar or higher luminosity than the surrounding area were observed by direct photography around the luminous flame of the emulsified fuel, whereas the frequency of occurrence of "bright spots" was almost negligible when n-dodecane was used. Observations indicated that the droplet flame rapidly expanded. This expansion was linked to secondary atomization phenomena such as puffing (i.e., vapor eruption from the droplet surface), partial micro-explosion (i.e., where a large portion of a droplet bursts), and micro-explosion (i.e., where the entire droplet bursts), which were visualized in the flame by magnified shadow imaging. It was suggested that secondary atomization caused rapid evaporation and spread of fuel vapor. The magnified shadow imaging technique provided a clear description of droplet behavior in the flame. Numerous puffing and micro-explosion were observed regardless of the flame emissions. In addition, it was observed that vapor blowout in secondary atomization accelerated droplet velocity, and led to the random movement of spray droplet. It was shown that the frequencies of secondary atomization increased in the downstream region where the luminous flame was formed. Secondary atomization occurred in droplets of various sizes in the downstream region, whereas it occurred in only small droplets in the upstream region where the luminous flame was not formed.

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Section: Introductionmentioning

confidence: 99%

Observation of droplet behavior of emulsified fuel in secondary atomization in flame

Watanabe

Shoji

Yamagaki

et al. 2014

JTST

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“…Combustion of any liquid fuel as particles or droplets occurs in several practical systems including internal combustion engines and liquid fuel fed industrial furnaces. Experiments for the burning of liquid fuel particles have been carried out in the past by several researchers [2][3][4][5][6][7][8]. Suspended droplets, free droplets, and liquid fuel fed through porous spheres have been studied.…”

Section: Introductionmentioning

confidence: 99%

Numerical Modeling of Steady Burning Characteristics of Spherical Ethanol Particles in a Spray Environment

Sahu

Raghavan

Pope

et al. 2011

Journal of Heat Transfer

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A numerical study of steady burning of spherical ethanol particles in a spray environment is presented. A spray environment is modeled as a high temperature oxidizer stream where the major products of combustion such as carbon dioxide and water vapor will be present along with reduced amounts of oxygen and nitrogen. The numerical model, which employs variable thermophysical properties, a global single-step reaction mechanism, and an optically thin radiation model, has been first validated against published experimental results for quasi-steady combustion of spherical ethanol particles. The validated model has been employed to predict the burning behavior of the ethanol particle in high temperature modified oxidizer environment. Results show that based on the amount of oxygen present in the oxidizer the burning rate constant is affected. The ambient temperature affects the burning rate constant only after a sufficient decrease in the oxygen content occurs. In pure air stream, ambient temperature variation does not affect the evaporation constant. Results in terms of burning rates, maximum temperature around the particle, and the evaporation rate constants are presented for all the cases. The variation of normalized Damköhler number is also presented to show the cases where combustion or pure evaporation would occur.

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“…Soot is one of the major sources of unsteadiness for the droplet combustion [13,14] and understanding of its influence on the droplet combustion is rather important. The magnitude of soot varies with oxygen concentration [15,16] in the ambience or with ambient pressure [15,17,18].…”

Section: Introductionmentioning

confidence: 99%

“…Inert gas in the ambience has large effects on the droplet combustion and experiments under microgravity have been conducted, especially for noble gases [16,19,20]. The inert components provide a wide range of the molecular weight, thermal properties and transport effects.…”

Section: Introductionmentioning

confidence: 99%

Combustion behaviors of isolated n-decane and ethanol droplets in carbon dioxide-rich ambience under microgravity

Nakaya¹,

Segawa²,

Kadota³

et al. 2011

Proceedings of the Combustion Institute

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Influence of oxygen concentration on the sooting behavior of ethanol droplet flames in microgravity conditions

Cited by 30 publications

References 18 publications

Observation of droplet behavior of emulsified fuel in secondary atomization in flame

Observation of droplet behavior of emulsified fuel in secondary atomization in flame

Numerical Modeling of Steady Burning Characteristics of Spherical Ethanol Particles in a Spray Environment

Combustion behaviors of isolated n-decane and ethanol droplets in carbon dioxide-rich ambience under microgravity

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