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On the extinction characteristics of alcohol droplet combustion under microgravity conditions – A numerical study

Published on Oct 1, 2012in Combustion and Flame 4.12
· DOI :10.1016/j.combustflame.2012.04.005
Tanvir Farouk17
Estimated H-index: 17
(Princeton University),
Frederick L. Dryer66
Estimated H-index: 66
(Princeton University)
Cite
Abstract
Abstract Quasi-steady burning and extinction of droplets are of interest from both fundamental and application viewpoints. The latter is related to combustor performance and fire safety issues in reduced gravity environments. Influences of diluent in the atmosphere on isolated droplet combustion characteristics including extinction provide insights to fire extinguishment phenomena and the effectiveness of various diluents as fire suppressants. Extinction of pure methanol and methanol–water droplets ranging from 1.5 to 7 mm size, for varying levels of ambient carbon-dioxide, helium and oxygen concentration – burning in a quiescent microgravity environment were studied numerically to compare the effectiveness of fire suppressant diluent selection and determining the limiting oxygen index. The results show distinct regimes of diffusive and radiative extinction. The transition from diffusive to radiative extinction is strongly influenced by the ambient diluent selection, especially by carbon dioxide concentration. Results for helium as the diluent showed increased burning rate and extinction due to diffusive heat loss. An “ extinction characteristic ” correlation is proposed that depends on burning rate, ambient diffusivity and flame standoff ratio. Recent methanol droplet experiments conducted over a wide range of operating conditions onboard the International Space Station were found to yield results that agree well with the proposed “ extinction characteristic ” correlation.
  • References (24)
  • Citations (20)
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References24
Newest
Published on Jul 1, 2012in International Journal of Chemical Kinetics 1.42
Michael P. Burke15
Estimated H-index: 15
(Princeton University),
Marcos Chaos22
Estimated H-index: 22
(FM Global)
+ 2 AuthorsStephen J. Klippenstein58
Estimated H-index: 58
(Argonne National Laboratory)
An updated H2/O2 kinetic model based on that of Li et al. (Int J Chem Kinet 36, 2004, 566–575) is presented and tested against a wide range of combustion targets. The primary motivations of the model revision are to incorporate recent improvements in rate constant treatment and resolve discrepancies between experimental data and predictions using recently published kinetic models in dilute, high-pressure flames. Attempts are made to identify major remaining sources of uncertainties, in both the ...
Published on Feb 1, 2012in Combustion and Flame 4.12
Sang Hee Won27
Estimated H-index: 27
(Princeton University),
Stephen Dooley23
Estimated H-index: 23
(Princeton University)
+ 1 AuthorsYiguang Ju54
Estimated H-index: 54
(Princeton University)
Abstract The extinction limits of diffusion flames have been measured experimentally and computed numerically for fuels of three different molecular structures pertinent to surrogate fuel formulation: n-alkanes, alkyl benzenes, and iso-octane. The focus of this study is to isolate the thermal and mass transport effects from chemical kinetic contributions to diffusion flame extinction, allowing for a universal correlation of extinction limit to molecular structure. A scaling analysis has been per...
Published on Jan 1, 2012in Combustion and Flame 4.12
Tanvir Farouk17
Estimated H-index: 17
(Princeton University),
Frederick L. Dryer66
Estimated H-index: 66
(Princeton University)
Abstract Tethered methanol droplet combustion in carbon dioxide enriched environment is simulated using a transient one-dimensional spherosymmetric droplet combustion model that includes the effects of tethering. A priori numerical predictions are compared against recent experimental data. The numerical predictions compare favorably with the experimental results and show significant effects of tethering on the experimental observations. The presence of a relatively large quartz fiber tether incr...
Published on Aug 1, 2011in Combustion Theory and Modelling 1.65
Tanvir Farouk17
Estimated H-index: 17
(Princeton University),
Frederick L. Dryer66
Estimated H-index: 66
(Princeton University)
Droplets tethering on fibers has become a well established technique for conducting droplet combustion experiments in microgravity conditions. The effects of these supporting fibers are frequently assumed to be negligible and are not considered in the experimental analysis or in numerical simulations. In this work, the effect of supporting fibers on the characteristics of microgravity droplet combustion has been investigated numerically; a priori predictions have then been compared with publishe...
Published on Aug 1, 2010in Combustion and Flame 4.12
Michael C. Hicks8
Estimated H-index: 8
(Glenn Research Center),
Vedha Nayagam13
Estimated H-index: 13
(Glenn Research Center),
Forman A. Williams48
Estimated H-index: 48
(UCSD: University of California, San Diego)
Diffusive extinction of methanol droplets with initial diameters between 1.25 mm and 1.72 mm, burning in a quiescent microgravity environment at one atmosphere pressure, was obtained experimentally for varying levels of ambient carbon-dioxide concentrations with a fixed oxygen concentration of 21% and a balance of nitrogen. These experiments serve as precursors to those which are beginning to be performed on the International Space Station and are motivated by the need to understand the effectiv...
Published on Mar 1, 2007in International Journal of Chemical Kinetics 1.42
Juan Li8
Estimated H-index: 8
(Princeton University),
Zhenwei Zhao13
Estimated H-index: 13
(Princeton University)
+ 3 AuthorsJames J. Scire3
Estimated H-index: 3
New experimental profiles of stable species concentrations are reported for formaldehyde oxidation in a variable pressure flow reactor at initial temperatures of 850–950 K and at constant pressures ranging from 1.5 to 6.0 atm. These data, along with other data published in the literature and a previous comprehensive chemical kinetic model for methanol oxidation, are used to hierarchically develop an updated mechanism for CO/H2O/H2/O2, CH2O, and CH3OH oxidation. Important modifications include re...
Published on Sep 1, 2003in Combustion and Flame 4.12
Andrei F. Kazakov24
Estimated H-index: 24
(Princeton University),
Jordan Conley2
Estimated H-index: 2
(Princeton University),
Frederick L. Dryer66
Estimated H-index: 66
(Princeton University)
Simulations of ethanol droplet combustion in microgravity have been conducted using a transient, finite-element, reactive flow model that includes a detailed description of gas-phase chemical kinetics and transport as well as non-luminous radiation. The results of the simulations are compared with a wide range of experimental data available in the literature. The experimental targets included ground-based, suspended droplet experiments, drop-tower experiments, and space-based experiments from th...
Published on Mar 1, 2000in Combustion and Flame 4.12
Keiichi Okai9
Estimated H-index: 9
(UTokyo: University of Tokyo),
Osamu Moriue8
Estimated H-index: 8
(UTokyo: University of Tokyo)
+ 5 AuthorsForman A. Williams48
Estimated H-index: 48
(UCSD: University of California, San Diego)
Abstract This paper presents the results of an experimental investigation on the combustion of single droplets and two-droplet arrays of pure methanol and methanol/dodecanol mixtures in air under microgravity conditions. The initial droplet diameters, d 0 , were nominally 0.9 mm. The independent experimental variables were the ambient pressure (0.1–9.0 MPa), fuel mixture ratio (methanol/dodecanol: 100/0–15/85), and interdroplet separation distance l ( l / d 0 = 2.3–8.0). For pure methanol, the r...
Published on Feb 1, 1999in Combustion and Flame 4.12
Anthony J. Marchese23
Estimated H-index: 23
(Rowan University),
Frederick L. Dryer66
Estimated H-index: 66
(Princeton University),
Vedha Nayagam13
Estimated H-index: 13
Abstract Transient, spherically symmetric, combustion of single and multi-component liquid n-alkane droplets is numerically simulated with a model that includes gas phase detailed, multi-component molecular transport and complex chemical kinetics. A compact semi-detailed kinetic mechanism for n-heptane and n-hexadecane oxidation consisting of 51 species (including He, Ar, and N 2 ) and 282 reactions is used to describe the gas phase. Non-luminous, gas phase radiative heat transfer and conservati...
Published on Jan 1, 1998
Anthony J. Marchese23
Estimated H-index: 23
(Princeton University),
Frederick L. Dryer66
Estimated H-index: 66
(Princeton University),
R.O. Colantonio4
Estimated H-index: 4
The results from methanol/water droplet combustion experiments conducted on two separate spacebased investigations are analyzed and compared against the predictions of a detailed numerical model. These two investigations (Fiber Supported Droplet Combustion Investigations 1 and 2) were conducted aboard Space Shuttle Columbia missions STS-73 and STS-94 in November 1995 and July 1997, respectively. In these experiments, pure methanol droplets and methanol/water droplets of 2–7 mm were suspended on ...
Cited By20
Newest
Published on Mar 1, 2019in Fuel Processing Technology 4.51
Jie Chen (Chongqing University), Yinhu Kang9
Estimated H-index: 9
(Chongqing University)
+ 7 AuthorsLin Mei3
Estimated H-index: 3
Abstract The near-extinction oscillatory dynamics and underlying mechanism of the dimethyl ether (DME) spherical diffusion flames in the hot- and cool-flame conditions were studied by the numerical approach with detailed chemistry and transport models. It was found that the self-sustaining spherical cool diffusion flame could be readily obtained in a wide range of parameters, and additionally, the flammability limit could be considerably extended by the cool-flame chemistry. Strong oscillations ...
Published on May 1, 2018in Applied Thermal Engineering 4.03
Anirudha Ambekar4
Estimated H-index: 4
(IITB: Indian Institute of Technology Bombay),
Arindrajit Chowdhury3
Estimated H-index: 3
(IITB: Indian Institute of Technology Bombay)
Abstract The burning rate constant of the droplets of a liquid fuel solely characterized by the thermo-physical properties of the fuel and the oxidizer is an intrinsic characteristic of the fuel. The classical quasi-steady approach enables estimation of such a parameter in a highly idealized scenario with a range of simplifying assumptions. Furthermore, this quasi-steady method requires the knowledge of the thermo-physical properties of the fuel along with the expected adiabatic flame temperatur...
Published on Feb 1, 2018in Combustion and Flame 4.12
Fahd E. Alam4
Estimated H-index: 4
(USC: University of South Carolina),
Sang Hee Won2
Estimated H-index: 2
(USC: University of South Carolina)
+ 1 AuthorsTanvir Farouk17
Estimated H-index: 17
(USC: University of South Carolina)
Abstract Cool flame combustion of individual and isolated sub-millimeter sized n -heptane ( n -C 7 H 16 ) and n -decane ( n -C 10 H 22 ) droplets are computationally investigated for atmospheric and higher operating pressure (25 atm) conditions with varying levels of ozone (O 3 ) mole fractions in the surroundings. A sphero-symmetric, one-dimensional, transient, droplet combustion model is utilized, employing reduced versions of detailed chemical kinetic models for the fuel species and an append...
Published on Feb 1, 2017in Combustion Science and Technology 1.56
Mithun Das11
Estimated H-index: 11
(Jadavpur University),
Arnab Chakraborty1
Estimated H-index: 1
(Jadavpur University)
+ 1 AuthorsApurba Kumar Santra8
Estimated H-index: 8
(Jadavpur University)
ABSTRACTThe combustion of liquid fuel droplets provides fundamental information that is relevant to spray combustion. A porous sphere setup has been used to investigate non-premixed combustion experimentally with three different liquid fuels, viz. methanol, diesel, and biodiesel (sunflower oil methyl ester). Experiments have been performed at atmospheric pressure with spheres of different diameters and over a range of free stream air velocities, resulting in different types of flames from envelo...
Published on Sep 1, 2016in Combustion and Flame 4.12
Yu Cheng Liu10
Estimated H-index: 10
(UM: University of Michigan),
Yuhao Xu7
Estimated H-index: 7
(Cornell University)
+ 1 AuthorsC. Thomas Avedisian14
Estimated H-index: 14
(Cornell University)
Abstract This paper reports the results of a comprehensive experimental study on the effect of initial droplet diameter ( D o ) over a very wide range (0.5 mm D o n -heptane, n -octane and n -decane – that are representative of components found in petroleum-based transportation fuels and their surrogates. Spherical symmetry in the burning process was promoted by carrying out the experiments in a reduced convection (stagnant ambience) and buoyancy (low gravity) environment using the facilities of...
Published on Jul 1, 2016in Combustion and Flame 4.12
Yu Cheng Liu10
Estimated H-index: 10
(UM: University of Michigan),
Fahd E. Alam4
Estimated H-index: 4
(USC: University of South Carolina)
+ 3 AuthorsTanvir I. Farouk4
Estimated H-index: 4
(USC: University of South Carolina)
Abstract This study reports results of experiments on the isolated droplet burning characteristics of butanol isomers ( n -, iso -, sec -, and tert -) under standard atmosphere conditions in an environment that promotes spherical combustion. The data are compared with predictions from a detailed numerical model (DNM) that incorporates complex combustion chemistry, radiative heat transfer, temperature dependent variable fluid properties, and unsteady gas and liquid transport. Computational predic...
Published on Mar 1, 2016in Fuel 5.13
Yuhao Xu7
Estimated H-index: 7
(Cornell University),
Ivan Keresztes18
Estimated H-index: 18
(Cornell University)
+ 3 AuthorsC. Thomas Avedisian14
Estimated H-index: 14
(Cornell University)
Abstract Fuels derived from bio-feedstocks have received significant attention for their potential to reduce the consumption of petroleum-based liquid fuels, either through blending or direct use. Biofuels produced from heterotrophic microalgae are particularly attractive because of fast conversion of sustainable plant sugars into renewable oils of controllable quality and composition, but without the need for sunlight or carbon from the atmosphere for growth. This paper describes the results of...
Published on Feb 1, 2016in Combustion Science and Technology 1.56
Fahd E. Alam4
Estimated H-index: 4
(USC: University of South Carolina),
Frederick L. Dryer4
Estimated H-index: 4
(Princeton University),
Tanvir I. Farouk4
Estimated H-index: 4
(USC: University of South Carolina)
ABSTRACTThe ‘FLame EXtinguishment’ (FLEX) program conducted by NASA on board the International Space Station (ISS) has been assisting in developing fire-safety protocols for low gravity applications through microgravity droplet combustion experiments. A wide range of fuels, including alcohols and alkanes, have been studied in different ambient conditions that also encompass the use of various diluent species and concentrations. A prime focus of the work has been to observe the relative effective...
Published on May 21, 2015in Energy & Fuels 3.02
Yuhao Xu7
Estimated H-index: 7
,
C. Thomas Avedisian14
Estimated H-index: 14
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...
Published on Jan 1, 2015in Procedia Engineering
Tanvir Farouk17
Estimated H-index: 17
(USC: University of South Carolina)
Abstract Cool flames are commonly associated with engine-knock phenomenon in spark ignition engines and autoignition in diesel engines, and results from low temperature partial oxidation of the fuel air mixture that eventually leads to hot flame ignition. However, the possibility of a cool flame supporting quasi-steady combustion of a fuel droplet has never been speculated, let alone been experimentally observed. Recent microgravity droplet combustion onboard the International Space Station (ISS...