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Experiments on Submillimeter Free Droplet Flame Extinction

Published on Jun 3, 2013in Combustion Science and Technology1.56
· DOI :10.1080/00102202.2012.759946
Benjamin D. Shaw13
Estimated H-index: 13
(UC Davis: University of California, Davis),
D. F. Wang2
Estimated H-index: 2
(UC Davis: University of California, Davis)
Cite
Abstract
Flame extinction of n-heptane, n-decane, and n-hexadecane droplets freely falling through hot gases from a flat flame burner was investigated. Initial droplet diameters were in the range 270–285 µm. The hot gases from the flat flame burner were injected into straight and contoured flow tubes, providing flow environments that had various degrees of convection. Transport properties were modified through inert gas substitution as an efficient means of adjusting both quasisteady burning rates and extinction conditions to satisfy experimental constraints. The experiments suggest that within the uncertainty of the measurements, external convective flows do not significantly influence extinction diameters for the droplet Reynolds number range 0.01 ≤ Re ≤ 0.1.
  • References (23)
  • Citations (2)
Cite
References23
Newest
Published on Jan 1, 2011
Anthony J. Marchese23
Estimated H-index: 23
(CSU: Colorado State University),
Timothy Vaughn7
Estimated H-index: 7
(CSU: Colorado State University)
+ 1 AuthorsFrederick L. Dryer66
Estimated H-index: 66
(Princeton University)
Abstract Recent optical engine studies have linked increases in NO x emissions from fatty acid methyl ester combustion to differences in the premixed autoignition zone of the diesel fuel jet. In this study, ignition of single, isolated liquid droplets in quiescent, high temperature air was considered as a means of gaining insight into the transient, partially premixed ignition conditions that exist in the autoignition zone of a fatty acid methyl ester fuel jet. Normal gravity and microgravity (1...
Published on Aug 1, 2010in Combustion and Flame4.12
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 Jul 27, 2009
Hugh W. Coleman12
Estimated H-index: 12
,
W. Glenn Steele5
Estimated H-index: 5
Preface. 1 Experimentation, Errors, and Uncertainty. 1-1 Experimentation. 1-2 Experimental Approach. 1-3 Basic Concepts and Definitions. 1-4 Experimental Results Determined from Multiple Measured Variables. 1-5 Guides and Standards. 1-6 A Note on Nomenclature. References. Problems. 2 Errors and Uncertainties in a Measured Variable. 2-1 Statistical Distributions. 2-2 Gaussian Distribution. 2-3 Samples from Gaussian Parent Population. 2-4 Statistical Rejection of Outliers from a Sample. 2-5 Uncert...
Published on Sep 1, 2003in Combustion and Flame4.12
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 Jan 1, 2001in AIAA Journal1.95
Benjamin D. Shaw1
Estimated H-index: 1
,
Bret D. Clark1
Estimated H-index: 1
,
Difei Wang1
Estimated H-index: 1
Results are presented from experiments on reduced-gravity combustion of individual heptane/hexadecane droplets. Initial droplet diameters ranged from 0.25 to 5.2 mm, and initial hexadecane mass fractions in the droplets were 0.058, 0.10, 0.20, and 0.40. Most droplets were burned in cabin air on Spacelab with an ambient oxygen mole fraction of about 0.21 and a pressure of about 0.1 MPa. Data were also obtained for small (0.25-mm) droplets in a ground-based apparatus that provides simulated reduce...
Published on Jun 1, 1999in Aiche Journal3.46
Difei F. Wang1
Estimated H-index: 1
(UC Davis: University of California, Davis),
Benjamin D. Shaw1
Estimated H-index: 1
(UC Davis: University of California, Davis),
Albert Yang1
Estimated H-index: 1
(UC Davis: University of California, Davis)
Experimental results on gasification behaviors of freely-falling spent alkylation sulfuric acid droplets in high-temperature environments are presented, as well as baseline data on evaporation of water droplets and sulfuric acid droplets. Low evaporation constants have been measured for sulfuric acid droplets and spent acid droplets (relative to water droplets). Shape distortions and fragmentation (microexplosions) of spent acid droplets were also observed, and it has been found that initial dro...
Published on Feb 1, 1999in Combustion and Flame4.12
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, 1998in AIAA Journal1.95
Vedha Nayagam13
Estimated H-index: 13
,
John B. Haggard5
Estimated H-index: 5
+ 4 AuthorsForman A. Williams48
Estimated H-index: 48
Results are presented from experiments on the combustion of freely floated n-heptane droplets in helium-oxygen environments conducted in Spacelab onboard the Space Shuttle Columbia during the first launch (STS-83) of the Microgravity Science Laboratory mission in April 1997. During this shortened flight, a total of eight droplets were burned successfully in nominally 300 K oxygen-helium atmospheres having oxygen mole fractions of 25, 30, and 35% at a total pressure of 1 atm. Initial droplet size...
Published on Jan 1, 1998in Combustion and Flame4.12
B.L. Zhang2
Estimated H-index: 2
(UCSD: University of California, San Diego),
Forman A. Williams48
Estimated H-index: 48
(UCSD: University of California, San Diego)
Abstract A simplified model for the time-dependent, spherically symmetrical combustion and extinction of methanol droplets is extended to account for a Lewis number of water vapor different from unit. A parametric study is performed, showing that, with water absorption and good mixing in the liquid, the burning time and extinction diameter achieve maxima for water Lewis numbers slightly less than unity in the gas phase. At high Lewis numbers, the smaller diffusion coefficient reduces the amount ...
Published on May 1, 1996in Combustion and Flame4.12
B.L. Zhang2
Estimated H-index: 2
(UCSD: University of California, San Diego),
J.M. Card4
Estimated H-index: 4
(SNL: Sandia National Laboratories),
Forman A. Williams48
Estimated H-index: 48
(UCSD: University of California, San Diego)
Abstract Asymptotic methods are employed to describe the flame structure and extinction of quasisteady, spherically symmetrical diffusion flames around methanol droplets. Starting with a short mechanism involving 14 steps, five of which are reversible, sequentially reduced overall descriptions of four, three, and two steps are obtained by investigating the character of the departure of the H atom and its associated radicals from steady states and by demonstrating in agreement with earlier work t...
Cited By2
Newest
Published on Jun 1, 2015in Flow Turbulence and Combustion2.37
Madjid Birouk16
Estimated H-index: 16
(UM: University of Manitoba),
Stephen L. Toth2
Estimated H-index: 2
(UM: University of Manitoba)
New experimental data on the effect of turbulence on the combustion of n-heptane and n-decane droplet at elevated pressure are reported. Turbulent flow field in the central volume of a spherical vessel was generated by a set of eight axial fans. Flow characterization demonstrated that turbulence is isotropic and homogeneous within the 40 mm central volume of the vessel. The combustion of n-heptane and n-decane droplet was examined by varying turbulence intensity via the fans rotational speed and...
Published on Jan 2, 2015in Combustion Science and Technology1.56
Narugopal Ghata1
Estimated H-index: 1
,
Benjamin D. Shaw13
Estimated H-index: 13
A detailed numerical investigation of combustion of unsupported and fiber supported n-heptane droplets in reduced gravity is presented. The primary focus is on the effects of support fibers on the droplet burning rates and flame structure. A 21-step n-heptane reaction mechanism consisting of 20 species is employed to model the combustion chemistry. The volume-of-fluid (VOF) method is employed to capture the liquid-gas interface while allowing for time-dependent two-phase multidimensional flows. ...