Combustion characteristics of water-in-oil emulsion droplets

Law, Chung K.; Lee, C.H.; Srinivasan, N.

doi:10.1016/0010-2180(80)90080-2

Cited by 102 publications

(35 citation statements)

References 11 publications

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“…In practice, the occurrence of micro-explosions has the potential to enhance fuel atomization in the combustion chamber, which is considered as an effective way of promoting efficient combustion in an engine. Several numerical and experimental studies have been performed to understand the micro-explosion behavior of emulsified fuel droplets [19][20][21][22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Experimental investigations on nucleation, bubble growth, and micro-explosion characteristics during the combustion of ethanol/Jet A-1 fuel droplets

Rao

Syam

Karmakar

et al. 2017

Experimental Thermal and Fluid Science

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The combustion characteristics of ethanol/Jet A-1 fuel droplets having three different proportions of ethanol (10%, 30%, and 50% by vol.) are investigated in the present study. The large volatility differential between ethanol and Jet A-1 and the nominal immiscibility of the fuels seem to result in combustion characteristics that are rather different from our previous work on butanol/Jet A-1 droplets (miscible blends). Abrupt explosion was facilitated in fuel droplets comprising lower proportions of ethanol (10%), possibly due to insufficient nucleation sites inside the droplet and the partially unmixed fuel mixture. For the fuel droplets containing higher proportions of ethanol (30% and 50%), micro-explosion occurred through homogeneous nucleation, leading to the ejection of secondary droplets and subsequent significant reduction in the overall droplet lifetime. The rate of bubble growth is nearly similar in all the blends of ethanol; however, the evolution of ethanol vapor bubble is significantly faster than that of a vapor bubble in the blends of butanol. The probability of disruptive behavior is considerably higher in ethanol/Jet A-1 blends than that of butanol/Jet A-1 blends. The Sauter mean diameter of the secondary droplets produced from micro-explosion is larger for blends with a higher proportion of ethanol. Both abrupt explosion and micro-explosion create a large-scale distortion of the flame, which surrounds the parent droplet. The secondary droplets generated from abrupt explosion undergo rapid evaporation whereas the secondary droplets from micro-explosion carry their individual flame and evaporate slowly. The growth of vapor bubble was also witnessed in the secondary droplets, which leads to the further breakup of the droplet (puffing/micro-explosion).

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Section: Introductionmentioning

confidence: 99%

Experimental investigations on nucleation, bubble growth, and micro-explosion characteristics during the combustion of ethanol/Jet A-1 fuel droplets

Rao

Syam

Karmakar

et al. 2017

Experimental Thermal and Fluid Science

View full text Add to dashboard Cite

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“…Recently, emission regulations for NOx, CO2 and soot from combustion engines have become more and more stringent due to growing concerns over environmental issues. Using emulsion (emulsified) fuel in combustion engines is considered as one promising solution (Dryer, 1977;Law et al, 1980;Lasheras et al, 1984;Sheng et al, 1994;Segawa et al, 2000;Kadota and Yamasaki, 2002;Fuchihata et al, 2003;Zeng and Lee, 2007;Tarlet et al, 2009;Watanabe et al, 2010;Suzuki et al, 2011;Watanabe and Okazaki, 2013;Shinjo et al, 2014). Emulsion fuel is a blend of immiscible liquids such as oil and water, formed with the help of surfactant agents.…”

Section: Introductionmentioning

confidence: 99%

“…In single-droplet experiments, a large droplet of O(1mm) was used to enable detailed observation and measurement (Law et al, 1980;Lasheras et al, 1984;Segawa et al, 2000;Kadota and Yamasaki, 2002;Suzuki et al, 2011). But its relevance to fuel spray droplets of O(10m) has not been well addressed.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, an improved understanding of the temperature distribution inside an emulsion droplet is needed as a key initial condition for accurate modeling of microexplosion/puffing, and will be aimed in this paper. In the literature, the heating process of emulsion droplets has been discussed (Law, 1977;Law et al, 1980;Law, 1982;Sirignano, 1983). However, the knowledge is still not sufficient to determine the initial conditions for microexplosion/puffing of emulsion droplets.…”

mentioning

confidence: 99%

“…Law (Law, 1977;Law et al, 1980;Law, 1982) has proposed models at two limits. In the distillation limit where the droplet surface is always covered by a uniform mixture of water and oil due to very strong internal circulation, the surface temperature is bound by the lower boiling point of water.…”

mentioning

confidence: 99%

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Modeling Temperature Distribution Inside an Emulsion Fuel Droplet Under Convective Heating: A Key to Predicting Microexplosion and Puffing

et al. 2016

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Microexplosion/puffing is rapid disintegration of a water-in-oil emulsion droplet caused by explosive boiling of embedded superheated water sub-droplets. To predict microexplosion/puffing, modeling the temperature distribution inside an emulsion droplet under convective heating is a prerequisite, since the temperature field determines the location of nucleation (vapor bubble initiation from superheated water). In the first part of the present study, convective heating of water-in-oil emulsion droplets under typical combustor conditions is investigated using high-fidelity simulation in order to accurately model inner-droplet temperature distribution. The shear force due to the ambient air flow induces internal circulation inside a droplet. It has been found that for droplets under investigation in the present study, the liquid Peclet number PeL is in a transitional regime of 100

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Flame spread behaviour of blended fuel droplet array

Park¹,

Kobayashi

Niioka

1999

Int. J. Energy Res.

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Experimental investigation of the effect of blended fuel on flame spread along droplet array has been conducted. Flame spread rate is measured using high‐speed chemiluminescence images of an OH radical. The flame spread is observed with the initial droplet diameter, droplet spacing, and the mixing ratio of n‐heptane and n‐hexadecane. The mode of flame spread is categorized into two types: a continuous mode and an intermittent one. It is seen that flame spread rate is sensitively dependent on the relative flame position to droplet spacing. For a large droplet, the flame spread time is governed by a volatile fuel (heptane), but for a small droplet, it is controlled by a less volatile fuel (hexadecane). Copyright © 1999 John Wiley & Sons, Ltd.

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Combustion characteristics of water-in-oil emulsion droplets

Cited by 102 publications

References 11 publications

Experimental investigations on nucleation, bubble growth, and micro-explosion characteristics during the combustion of ethanol/Jet A-1 fuel droplets

Experimental investigations on nucleation, bubble growth, and micro-explosion characteristics during the combustion of ethanol/Jet A-1 fuel droplets

Modeling Temperature Distribution Inside an Emulsion Fuel Droplet Under Convective Heating: A Key to Predicting Microexplosion and Puffing

Flame spread behaviour of blended fuel droplet array

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