Microgravity Droplet Combustion: An Inverse Scale Modeling Problem

Nayagam, Vedha; Marchese, Anthony J.; Sacksteder, Kurt R.

doi:10.1007/978-1-4020-8682-3_13

Cited by 4 publications

(16 citation statements)

References 14 publications

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“…The limited data suggest that D oI ∼1 mm. The upper range ( D oII ) is unknown though probably in the range of 2 mm [33] . One of the purposes of the present investigation is to examine the droplet burning process over the widest range 0.5 mm < D o < 5 mm to elucidate various regimes of burning.…”

Section: Introductionmentioning

confidence: 99%

“…This trend is consistent with detailed numerical modeling that also predicts K to be independent of D o [8,13] . This approximation would remain in effect for droplet sizes down to those found in sprays [33][34][35] . The upper bound of droplet diameter for radiation to be unimportant is indicated as D oI in Fig.…”

Section: Introductionmentioning

confidence: 99%

“…This trend has not been fully explained, owing in part to the inability to model all of the important processes in droplet burning (i.e., unsteady transport, variable properties, soot formation, radiation, complex combustion chemistry). Scale analysis [32,33] as applied to droplet burning offers capabilities to develop an understanding of the important variables involved. Appendix A discusses this approach.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Comprehensive study of initial diameter effects and other observations on convection-free droplet combustion in the standard atmosphere for n-heptane, n-octane, and n-decane

Liu

Hicks

et al. 2016

Combustion and Flame

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comprehensive study of initial diameter effects and other observations on convection-free droplet combustion in the standard atmosphere for n-heptane, n-octane, and n-decane

Liu

Hicks

et al. 2016

Combustion and Flame

View full text Add to dashboard Cite

“…In other words, the burning rate constant of smaller droplets can be determined by the accurate experimental results of larger droplets. However, the combustion behaviors predicted by the D 2 -law model are not always observed during experiments under real conditions …”

Section: Introductionmentioning

confidence: 98%

“…The droplet combustion duration required for a given size may be easily calculated based on the knowledge of specific burning rate. It is worth noting that the classical theory employs several assumptions in extensions to the spherically symmetric method, such as gas-phase quasi-steadiness, constant gas-phase transport properties, infinitely fast gas-phase chemistry, and no radiative heat loss. − It is easy to understand that the predicted burning rate constant is independent of the initial droplet size according to the classic droplet combustion theory. In other words, the burning rate constant of smaller droplets can be determined by the accurate experimental results of larger droplets.…”

Section: Introductionmentioning

confidence: 99%

Experimental Studies on Combustion and Microexplosion Characteristics of N-Alkane Droplets

et al. 2020

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A detailed experimental investigation on the effect of thermal properties on single droplet combustion characteristics has been performed at room temperature and atmospheric pressure under normal gravity with four n-alkanes (n-octane, n-dodecane, n-tetradecane, and n-hexadecane). The evolution of suspended droplet diameter and the global flame over time were obtained using microscopic and direct photography simultaneously. The results show that the n-alkane droplets used in this study exhibited similar D 2-law curve characteristics and the droplet shape of single component is quasi-spherical throughout the whole combustion duration. The n-alkanes with lower boiling point and high volatility present a higher burning rate and shorter combustion duration, and there is no expansion process during the evaporation period. Strong microexplosion and fluctuation on droplet diameter were observed when the thermal properties of the multicomponent are sufficiently different. The reason is that the bubbles nucleate, grow, and rupture continuously by heating the components of lower boiling point and high volatility in multicomponent droplets. The thermal properties and mixing ratio of the components in the multicomponent droplet and the formation position of the bubbles have an important influence on the microexplosive combustion and its intensity. Besides, there is an inverse power relationship between the burning rate constant of n-alkane droplets and initial droplet diameter (D 0 > 1 mm).

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Combustion of n-Butanol, Gasoline, and n-Butanol/Gasoline Mixture Droplets

Avedisian

2015

Energy Fuels

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Fuels derived from biofeedstocks are receiving attention for their potential as additives to conventional petroleum-based transportation fuels. Normal butanol, in particular, can enhance performance compared to ethanol because of its higher energy density. To better understand the combustion dynamics of n-butanol in the context of gasoline, experiments are reported here to examine the isolated droplet combustion characteristics of an 87 octane (ethanol-free) gasoline and a mixture of gasoline (0.9, v/v) and n-butanol (0.l, v/v, B10), along with n-butanol. The experiments are performed in an ambience that minimizes convection and promotes spherical droplet flames. The initial droplet diameters range from 0.52 to 0.63 mm, and the experiments are carried out in room-temperature air at normal atmospheric pressure. Measurements of the evolution of the droplet diameter show that butanol and B10 droplets have burning rates that are almost identical to gasoline, even though other features of the burning process, such as soot formation and the relative position of the droplet and flame, are quite different. With butanol mixed with gasoline, the mixture flames are comparatively closer to the droplet than for gasoline droplets. A scale analysis is developed that expresses the droplet burning rate in terms of temperature-dependent properties. The results support the experimentally observed similarity of burning rates for butanol, gasoline, and their mixtures, even though soot formation is neglected.

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Microgravity Droplet Combustion: An Inverse Scale Modeling Problem

Cited by 4 publications

References 14 publications

Comprehensive study of initial diameter effects and other observations on convection-free droplet combustion in the standard atmosphere for n-heptane, n-octane, and n-decane

Comprehensive study of initial diameter effects and other observations on convection-free droplet combustion in the standard atmosphere for n-heptane, n-octane, and n-decane

Experimental Studies on Combustion and Microexplosion Characteristics of N-Alkane Droplets

Combustion of n-Butanol, Gasoline, and n-Butanol/Gasoline Mixture Droplets

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