Surface tension effects during low-Reynolds-number methanol droplet combustion

Vasudevan Raghavan, Daniel N. Pope, Damon Howard, George Gogos

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

A numerical investigation of methanol droplet combustion in a zero-gravity, low-pressure, and low-temperature environment is presented. Simulations have been carried out using a predictive, transient, and axisymmetric model, which includes droplet heating, liquid-phase circulation, and water absorption. A low initial Reynolds number ( Re0 = 0.01) is used to impose a weak gas-phase convective flow, introducing a deviation from spherical symmetry. The resulting weak liquid-phase circulation is greatly enhanced due to surface tension effects, which create a complex, time-varying, multicellular flow pattern within the liquid droplet. The complex flow pattern, which results in nearly perfect mixing, causes increased water absorption within the droplet, leading to larger extinction diameters. It is shown that, for combustion of a 0.43-mm droplet in a nearly quiescent environment ( Re0 = 0.01 ) composed of dry air, the extinction diameter is 0.11 mm when surface tension effects are included, and 0.054 mm when surface tension effects are neglected. Experimental work available in the literature for a 0.43-mm droplet reported extinction diameters in the range of 0.16 to 0.19 mm. Results for combustion in a nearly quiescent environment ( Re0 = 0.01 ) with varying initial droplet diameters (0.16 to 1.72 mm) show that including the effect of surface tension results in approximately linear variation of the extinction diameter with the initial droplet diameter, which is in agreement with theoretical predictions and experimental measurements. In addition, surface tension effects are shown to be important even at initial Reynolds numbers as high as 5.

Original languageEnglish (US)
Pages (from-to)791-807
Number of pages17
JournalCombustion and Flame
Volume145
Issue number4
DOIs
StatePublished - Jun 1 2006

Fingerprint

low Reynolds number
Methanol
Surface tension
interfacial tension
Reynolds number
methyl alcohol
extinction
flow distribution
liquid phases
Water absorption
low temperature environments
Flow patterns
weightlessness
Liquids
convective flow
Boiler circulation
water
low pressure
vapor phases
deviation

Keywords

  • Droplet combustion
  • Extinction
  • Methanol
  • Surface tension
  • Water absorption

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Physics and Astronomy(all)

Cite this

Surface tension effects during low-Reynolds-number methanol droplet combustion. / Raghavan, Vasudevan; Pope, Daniel N.; Howard, Damon; Gogos, George.

In: Combustion and Flame, Vol. 145, No. 4, 01.06.2006, p. 791-807.

Research output: Contribution to journalArticle

Raghavan, Vasudevan ; Pope, Daniel N. ; Howard, Damon ; Gogos, George. / Surface tension effects during low-Reynolds-number methanol droplet combustion. In: Combustion and Flame. 2006 ; Vol. 145, No. 4. pp. 791-807.
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