Numerical analysis of ignition of fuel droplet array in hot stagnant air

Megumi Goto, Yiguang Ju, Takashi Niioka

Research output: Contribution to journalConference articlepeer-review

14 Scopus citations


Numerical analysis was conducted to simulate the ignition phenomena of a fuel droplet array in hot stagnant air. Previous experimental results showed that ignition times of an n-heptane droplet array quickly put into quiescent hot air were less than the ignition time of a single droplet. The objective of the present study was to clarify this interesting behavior of ignition time by numerical analysis. We assumed that a heptane droplet array with a droplet diameter of 0.75 to 1.25 mm and spacing of 4 to 20 mm was immersed in hot air with a temperature of 1123 K at time zero. The unsteady equation set for the array system was solved numerically by means of the finite-difference method. The results showed that ignition times became shorter than that of a single droplet as the droplet spacing decreased and that ignition times increased rapidly when the spacing further decreased. These ignition time behaviors were consistent with experimental results. Time-dependent temperature distributions indicated that the first ignition position(s) was located between droplets when the ignition time was less than that of a single droplet. When the spacing was smaller, an intense reaction region surrounded the array as a cylindrical tube. The basic mechanism of the shorter ignition time of a droplet array is a slight decrease of the vaporized fuel mass flux due to the suppression of the increase in droplet surface temperature in the array.

Original languageEnglish (US)
Pages (from-to)1959-1966
Number of pages8
JournalSymposium (International) on Combustion
Issue number2
StatePublished - 1998
Event27th International Symposium on Combustion - Boulder, CO, United States
Duration: Aug 2 1998Aug 7 1998

All Science Journal Classification (ASJC) codes

  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Mechanical Engineering
  • Physical and Theoretical Chemistry
  • Fluid Flow and Transfer Processes


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