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Combustion behaviors of isolated n-decane and ethanol droplets in carbon dioxide-rich ambience under microgravity

Published on Jan 1, 2011
· DOI :10.1016/j.proci.2010.06.136
Shinji Nakaya8
Estimated H-index: 8
(OPU: Osaka Prefecture University),
Daisuke Segawa10
Estimated H-index: 10
(OPU: Osaka Prefecture University)
+ 2 AuthorsTomoya Furuta1
Estimated H-index: 1
(OPU: Osaka Prefecture University)
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Abstract
Abstract The burning and sooting behaviors of isolated fuel droplets for ethanol and n -decane are examined in high concentration of the ambient carbon dioxide under microgravity. A quartz fiber with the diameter of 50 μm maintains the droplet in the center of the combustion chamber and the range in the initial droplet diameter is from 0.30 to 0.80 mm. The ambience consists of oxygen, nitrogen and carbon dioxide. The concentration of oxygen is 21% in volume, and that of carbon dioxide is varied from 0% to 60% in volume. Detail measurements of the projected image of the droplet are conducted by using a high speed video camera and the effective droplet diameter squared are calculated from the surface area of the rotating body of the projected object. From evolutions of the droplet diameter squared, the instantaneous burning rates are calculated. Time history of the instantaneous burning rate clearly represents the droplet combustion events, such as the initial thermal expansion, ignition and following combustion. The instantaneous burning rate for n-decane shows an increasing trend during combustion, while that for non-sooting ethanol remains almost constant or shows a decreasing trend. A slight stepwise increase in the instantaneous burning rate is observed for larger n -decane droplets in air, which may be attributed to soot accumulation. However, this behavior of the burning rate disappears in higher concentration of carbon dioxide. Direct observation of the droplet flame indicates suppression of soot production in higher concentration of carbon dioxide and the suppression is enhanced for smaller droplet.
  • References (32)
  • Citations (6)
Cite
References32
Newest
Justin Dzik1
Estimated H-index: 1
(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)
The ignition process and burning characteristics of fiber-supported n-heptane fuel droplets in carbon dioxide enriched and varying pressure environments have been studied under normal gravity. Measured values of droplet burning rates, flame dimensions, broad-band radiant emission, and ignition times were compared to droplets burning in standard air conditions. The burning rate constants increased with increasing carbon dioxide concentration or pressure. For 21% ambient oxygen concentration ignit...
Published on Nov 30, 2009in Combustion Science and Technology1.56
J. B. Wei4
Estimated H-index: 4
(UC Davis: University of California, Davis),
Benjamin D. Shaw13
Estimated H-index: 13
(UC Davis: University of California, Davis)
Reduced gravity combustion experiments were performed with individual fiber-supported propanol droplets that were initially about 1 mm in diameter. The environment was composed of an oxygen-inert mixture. Helium, argon, xenon, nitrogen, and carbon dioxide were used as inerts, the oxygen mole fraction was 0.21, and the pressure was 0.03, 0.1, or 0.3 MPa. Use of helium caused extinction at 0.03 MPa and 0.1 MPa, but extinction was not observed in other oxygen-inert experiments within the 2.2 s redu...
Published on Nov 30, 2009in Combustion Science and Technology1.56
Shinji Nakaya8
Estimated H-index: 8
(OPU: Osaka Prefecture University),
Mitsuhiro Tsue5
Estimated H-index: 5
(UTokyo: University of Tokyo)
+ 4 AuthorsMichikata Kono16
Estimated H-index: 16
(UTokyo: University of Tokyo)
Experiments have been carried out on the effects of pre-vaporized fuel in the ambience on spontaneous ignition behavior of isolated fuel droplets. An isolated droplet of n-heptane or n-dodecane, which is sustained by a quartz fiber, is inserted into a high-temperature gas field including fuel in the electric furnace. Methane and n-heptane are selected as fuels of the ambience. The ambient pressure and the temperature are set to be 0.3 MPa and 700 K, respectively, in order to prevent the consumpt...
Published on Jan 1, 2009in Combustion and Flame4.12
Mehdi Jangi11
Estimated H-index: 11
(Tohoku University),
S. Sakurai3
Estimated H-index: 3
+ 1 AuthorsHideaki Kobayashi5
Estimated H-index: 5
(Tohoku University)
A study on droplet combustion in unsteady force convection at high pressure under microgravity conditions was performed. The hysteresis loop of the instantaneous burning rate of a single suspended 1-butanol droplet was observed for the first time. Results showed that the classical quasi-steady film model cannot describe droplet combustion in an unsteady flow. Based on precise experimental observation and by utilizing dimensional analysis of the energy conservation equation, a new criterion is he...
Published on Jan 1, 2007
J.H. Bae1
Estimated H-index: 1
(Cornell University),
C.T. Avedisian24
Estimated H-index: 24
(Cornell University)
In this paper, we study the influence of inert concentration and initial droplet diameter on nonane (C9H20) droplet combustion in an environment that promotes spherical droplet flames. The oxygen concentration is fixed while the inert is varied between nitrogen and helium. A range of initial droplet diameters (Do) are examined in each ambient gas: 0.4 mm < Do < 0.8 mm; and an oxidizing ambiance consisting of 30% oxygen (fixed) and 70% inert (fixed), with the inert in turn composed of mixtures of...
Published on Jan 1, 2007
Ahmet Yozgatligil8
Estimated H-index: 8
(Drexel University),
Seul-Hyun Park7
Estimated H-index: 7
(Drexel University)
+ 2 AuthorsFrederick L. Dryer66
Estimated H-index: 66
(Princeton University)
Abstract The influence of oxygen (O 2 ) concentration and inert on the sooting and burning behavior of large ethanol droplets under microgravity conditions was investigated through measurements of burning rate, flame temperature, sootshell diameter, and soot volume fraction. The experiments were performed at the NASA Glenn Research Center (GRC) 2.2 s drop tower in Cleveland, OH. Argon (Ar), helium (He), and nitrogen (N 2 ) were used as the inerts and the O 2 concentration was varied between 21% ...
Published on Jun 1, 2006in Microgravity Science and Technology1.97
S. M. Dakka1
Estimated H-index: 1
(UC Davis: University of California, Davis),
Benjamin D. Shaw13
Estimated H-index: 13
(UC Davis: University of California, Davis)
Reduced-gravity experiments on combustion of individual 1-propanol droplets with initial diameters of about 1 mm were conducted in air at standard temperature and with pressures ranging from 0.1 MPa to 1.0 MPa. Flames at 0.1 MPa were non-sooting with blue coloring during most of the combustion process. At higher pressures, flames exhibited significant amounts of soot during most of the combustion history. Flames were also non-spherical at elevated pressure, which is likely a result of the increa...
Published on May 1, 2006in Combustion and Flame4.12
J.H. Bae2
Estimated H-index: 2
(Cornell University),
C.T. Avedisian24
Estimated H-index: 24
(Cornell University)
Abstract An experimental study of droplet combustion of nonane (C 9 H 20 ) at elevated pressures burning in air is reported using low gravity and small droplets to promote spherical gas-phase symmetry at pressures up to 30 atm (absolute). The initial droplet diameters range from 0.57 to 0.63 mm and they were ignited by two electrically heated hot wires positioned horizontally on opposite sides of the droplet. The droplet and flame characteristics were recorded by a 16-mm high-speed movie and a h...
Published on Mar 1, 2005in Microgravity Science and Technology1.97
A. Boisjoli1
Estimated H-index: 1
(Laval University),
J.-C. Leclerc2
Estimated H-index: 2
(Laval University)
+ 3 AuthorsS. Raymond1
Estimated H-index: 1
(National Research Council)
Silicon nanocrystal aggregates have been produced in an inert argon gas by a pulsed laser vaporization-condensation technique using the second harmonic of a Nd: YAG laser. In our previous work, it has been shown that materials generated by evaporation-condensation technique present a variety of structures depending on the conditions of production. A theoretical model has been elaborated from a multitude of metallic samples, taking into consideration the effect of the main physical factors on the...
Published on Mar 1, 2005in Microgravity Science and Technology1.97
Benjamin D. Shaw13
Estimated H-index: 13
(UC Davis: University of California, Davis),
V. Dee1
Estimated H-index: 1
(UC Davis: University of California, Davis)
Reduced gravity experiments were performed to investigate droplet combustion behaviors in environments with He, N2, or Xe as diluents. These diluents have significant differences in molecular weight, allowing investigation of Soret transport (species diffusion from temperature gradients) and differences in binary diffusion coefficients. The droplets, which were initially about 1 mm in diameter, were composed of decane/hexadecane mixtures with initial hexadecane mass fractions of 0, 0.05 and 0.20...
Cited By6
Newest
Published on Jan 1, 2019in Fuel5.13
Yoshinari Kobayashi3
Estimated H-index: 3
(Gidai: Gifu University),
Takeshi Tsujino31
Estimated H-index: 31
(UTokyo: University of Tokyo)
+ 2 AuthorsShuhei Takahashi (Gidai: Gifu University)
Abstract This work addressed laser-induced spark ignition (LSI) of dimethyl ether (DME)-air mixtures in a microgravity environment which was simulated in a laboratory-scale drop tower, to study fundamental ignition characteristics in microgravity. A laser-induced spark was adopted as a pilot source because LSI has potential benefits as compared to conventional electrical spark ignition: no wall effects, no heat-loss to electrodes, etc. Ignition characteristics, therefore, can be investigated wit...
Published on Jan 1, 2013
Shinji Nakaya8
Estimated H-index: 8
(UTokyo: University of Tokyo),
Kotaro Fujishima1
Estimated H-index: 1
(UTokyo: University of Tokyo)
+ 2 AuthorsDaisuke Segawa10
Estimated H-index: 10
(OPU: Osaka Prefecture University)
Abstract The burning characteristics of isolated fuel droplets for ethanol, 1-butanol and n -decane were experimentally examined in carbon dioxide-rich or argon-rich environments under microgravity. The ambience consisted of oxygen, nitrogen, carbon dioxide and argon. The concentration of oxygen was fixed to be 21% in volume percentage, and that of carbon dioxide or argon was varied from 0% to 60% in volume percentage. Detailed measurements of the droplet surface areas were conducted using a hig...
Published on Feb 1, 2012in Combustion Theory and Modelling1.65
Klaus G. Moesl2
Estimated H-index: 2
(TUM: Technische Universität München),
Joachim Schwing5
Estimated H-index: 5
(TUM: Technische Universität München),
Thomas Sattelmayer28
Estimated H-index: 28
(TUM: Technische Universität München)
An approach for modelling and simulation of the generation of nitrogen oxide (NOx) in the gas phase surrounding single burning droplets is presented. Assuming spherical symmetry (no gravity, no forced convection), the governing equations are derived first. Then simplifications are introduced and it is proven that they are appropriate. The influences of the initial droplet diameter, the ambient conditions, and the droplet pre-vapourisation on NOx are investigated. The fuel of choice is n-decane (...
Published on Jan 1, 2012in Combustion and Flame4.12
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...
Vaibhav Kumar Sahu1
Estimated H-index: 1
(Indian Institute of Technology Madras),
Vasudevan Raghavan13
Estimated H-index: 13
(Indian Institute of Technology Madras)
+ 1 AuthorsGeorge Gogos17
Estimated H-index: 17
A numerical study of steady burning of spherical ethanol particles in a spray environment is presented. A spray environment is modeled as a high temperature oxidizer stream where the major products of combustion such as carbon dioxide and water vapor will be present along with reduced amounts of oxygen and nitrogen. The numerical model, which employs variable thermophysical properties, a global single-step reaction mechanism, and an optically thin radiation model, has been first validated agains...
Published on Jan 1, 2011
Vaibhav Kumar Sahu1
Estimated H-index: 1
,
Vasudevan Raghavan13
Estimated H-index: 13
+ 1 AuthorsGeorge Gogos17
Estimated H-index: 17
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