A simple model for puffing/micro-explosions in water-fuel emulsion droplets

Sergei Sazhin, Oyuna Rybdylova, Cyril Crua, Morgan Heikal, M. Ismael, Z. Nissar, Rashid Aziz

Research output: Contribution to journalArticleResearchpeer-review

Abstract

A new simple model for the puffing/micro-explosion of water-fuel emulsion droplets is suggested. The model is based on the assumption that a spherical water sub-droplet is located in the centre of a larger fuel droplet. The fuel is approximated by n-dodecane. The fuel droplet surface temperature is assumed to be fixed, and fuel evaporation is ignored. The heat conduction equation is solved inside this composite droplet with the Dirichlet boundary condition at the surface of the fuel droplet. The time instant when the temperature at the interface between water and fuel reaches the boiling temperature of water is associated with the start of the puffing process leading to micro-explosion. This time is referred to as the time to puffing, or micro-explosion delay time. When the fuel surface temperature is equal to the boiling temperature of fuel then this time is expected to be the shortest of the possible times. The predictions of the model are shown to be in agreement with available experimental data. The model predicts an increase in this time with increase in the fuel droplet size for fixed water and fuel mass fractions, in agreement with observations.
Original languageEnglish
Pages (from-to)815-821
Number of pages7
JournalInternational Journal of Heat and Mass Transfer
Volume131
DOIs
Publication statusPublished - 28 Mar 2019

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Explosions
Emulsions
Water
Boiling liquids
Temperature
Heat conduction
Time delay
Evaporation
Boundary conditions
Composite materials

Keywords

  • micro-explosions
  • n-dodecane
  • droplets
  • pung
  • heat conduction equation
  • Heat conduction equation
  • Droplets
  • Puffing
  • n-Dodecane
  • Micro-explosions

Cite this

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title = "A simple model for puffing/micro-explosions in water-fuel emulsion droplets",
abstract = "A new simple model for the puffing/micro-explosion of water-fuel emulsion droplets is suggested. The model is based on the assumption that a spherical water sub-droplet is located in the centre of a larger fuel droplet. The fuel is approximated by n-dodecane. The fuel droplet surface temperature is assumed to be fixed, and fuel evaporation is ignored. The heat conduction equation is solved inside this composite droplet with the Dirichlet boundary condition at the surface of the fuel droplet. The time instant when the temperature at the interface between water and fuel reaches the boiling temperature of water is associated with the start of the puffing process leading to micro-explosion. This time is referred to as the time to puffing, or micro-explosion delay time. When the fuel surface temperature is equal to the boiling temperature of fuel then this time is expected to be the shortest of the possible times. The predictions of the model are shown to be in agreement with available experimental data. The model predicts an increase in this time with increase in the fuel droplet size for fixed water and fuel mass fractions, in agreement with observations.",
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year = "2019",
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A simple model for puffing/micro-explosions in water-fuel emulsion droplets. / Sazhin, Sergei; Rybdylova, Oyuna; Crua, Cyril; Heikal, Morgan; Ismael, M.; Nissar, Z.; Aziz, Rashid.

In: International Journal of Heat and Mass Transfer, Vol. 131, 28.03.2019, p. 815-821.

Research output: Contribution to journalArticleResearchpeer-review

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AU - Nissar, Z.

AU - Aziz, Rashid

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