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n-Butanol droplet combustion: Numerical modeling and reduced gravity experiments

Published on Jan 1, 2015
· DOI :10.1016/j.proci.2014.06.043
Fahd E. Alam4
Estimated H-index: 4
(USC: University of South Carolina),
Yu Cheng Liu10
Estimated H-index: 10
(Cornell University)
+ 2 AuthorsTanvir I. Farouk4
Estimated H-index: 4
(USC: University of South Carolina)
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Abstract
Abstract Recent interest in alternative and bio-derived fuels has emphasized butanol over ethanol as a result of its higher energy density, lower vapor pressure and more favorable gasoline blending properties. Numerous efforts have examined the combustion of butanol from the perspective of low dimensional gas-phase transport configurations that facilitate modeling and validation of combustion kinetics. However, fewer studies have focused on multiphase butanol combustion, and none have appeared on isolated droplet combustion that couples experiments with robust modeling of the droplet burning process. This paper presents such an experimental/numerical modeling study of isolated droplet burning characteristics of n -butanol. The experiments are conducted in an environment that simplifies the transport process to one that is nearly one-dimensional as promoted by burning in a reduced gravity environment. Measurements of the evolution of droplet diameter ( D o  = 0.56–0.57 mm), flame standoff ratio ( FSR  ≡  D f / D ) and burning rate ( K ) are made in the standard atmosphere under reduced gravity and the data are compared against numerical simulation. The detailed model is based on a comprehensive time-dependent, sphero-symmetric droplet combustion simulation that includes spectrally resolved radiative heat transfer, multi-component diffusive transport, full thermal property variations and detailed chemical kinetic. The simulations are carried out using both a large order kinetic mechanism (284 species, 1892 reactions) and a reduced order mechanism (44 species, 177 reactions). The results show that the predicted burning history and flame standoff ratios are in good agreement with the measurements for both the large and reduced order mechanisms. Additional simulations are conducted for varying oxygen concentration to determine the limiting oxygen index and to elucidate the kinetic processes that dictate the extinction of the flame at these low oxygen concentrations.
  • References (34)
  • Citations (10)
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References34
Newest
Published on Mar 1, 2013in Combustion and Flame4.12
Hu Wang17
Estimated H-index: 17
(UW: University of Wisconsin-Madison),
Rolf D. Reitz71
Estimated H-index: 71
(UW: University of Wisconsin-Madison)
+ 3 AuthorsLu Qiu7
Estimated H-index: 7
(UW: University of Wisconsin-Madison)
A reduced chemical reaction mechanism was developed for modeling the combustion process and soot emissions for both non-oxygenated and oxygenated hydrocarbon fuels. A detailed poly-aromatic hydrocarbon (PAH) mechanism was reduced and embedded into a reduced n-heptane mechanism for describing the formation of PAH up to four rings (A4) and for soot prediction. A reduced n-butanol mechanism was combined with the n-heptane-PAH mechanism to investigate of effects of oxygenated n-butanol fuels on comb...
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 Jan 1, 2013
Tanvir Farouk17
Estimated H-index: 17
(Princeton University),
Yu Cheng Liu10
Estimated H-index: 10
(Cornell University)
+ 2 AuthorsFrederick L. Dryer66
Estimated H-index: 66
(Princeton University)
Abstract Combustion characteristics of isolated sub-millimeter sized methyl butanoate (MB) droplets are studied at low gravity (10 −4 m/s 2 ) in a 1.2 s drop tower. In the experiments, droplets were grown and deployed onto the intersection of two 14 μm silicon carbide fibers in a cross-string arrangement and exposed to symmetrically placed spark ignition sources. The initial droplet diameter was fixed at 0.54 ± 0.01 mm, and experiments were carried out in room temperature air at atmospheric pres...
Published on Sep 20, 2012in Energy & Fuels3.02
Jianghuai Cai13
Estimated H-index: 13
,
Lidong Zhang25
Estimated H-index: 25
+ 4 AuthorsFei Qi37
Estimated H-index: 37
n-Butanol pyrolysis in a flow reactor was investigated at the pressures of 5, 30, 80, 200, and 760 Torr. Synchrotron vacuum ultraviolet photoionization mass spectrometry was used for the identification of pyrolysis species and the measurement of their mole fractions. A detailed kinetic model consisting of 121 species and 658 reactions was developed to simulate the n-butanol pyrolysis. To enhance the accuracy of the model, the rate constants of unimolecular reactions of n-butanol and β-scission r...
Published on Sep 5, 2012in Image Analysis & Stereology1.78
Christopher Dembia6
Estimated H-index: 6
(Cornell University),
Yu Cheng Liu10
Estimated H-index: 10
(Cornell University),
C. Thomas Avedisian14
Estimated H-index: 14
(Cornell University)
A simple automated image analysis algorithm has been developed that processes consecutive images from high speed, high resolution digital images of burning fuel droplets. The droplets burn under conditions that promote spherical symmetry. The algorithm performs the tasks of edge detection of the droplet’s boundary using a grayscale intensity threshold, and shape fitting either a circle or ellipse to the droplet’s boundary. The results are compared to manual measurements of droplet diameters done...
Published on Jun 1, 2012in Combustion and Flame4.12
S.M. Sarathy26
Estimated H-index: 26
(LLNL: Lawrence Livermore National Laboratory),
Stijn Vranckx8
Estimated H-index: 8
(RWTH Aachen University)
+ 8 AuthorsRavi X. Fernandes16
Estimated H-index: 16
(RWTH Aachen University)
Abstract Alcohols, such as butanol, are a class of molecules that have been proposed as a bio-derived alternative or blending agent for conventional petroleum derived fuels. The structural isomer in traditional “bio-butanol” fuel is 1-butanol, but newer conversion technologies produce iso-butanol and 2-butanol as fuels. Biological pathways to higher molecular weight alcohols have also been identified. In order to better understand the combustion chemistry of linear and branched alcohols, this st...
Published on Feb 1, 2012in Combustion and Flame4.12
Yu Cheng Liu10
Estimated H-index: 10
(Cornell University),
C. Thomas Avedisian14
Estimated H-index: 14
(Cornell University)
Abstract The droplet burning characteristics of binary blends of iso-octane, n -heptane and toluene were studied in an ambience that minimizes external convection and promotes spherical droplet flames. The results are compared to gasoline (87 octane rating). The initial droplet diameter was fixed at 0.51 ± 0.02 mm and the experiments were carried out in room temperature air. Measurements of the evolution of droplet diameter show that iso-octane, n -heptane and their mixtures have almost identica...
Published on Jan 1, 2012in AIAA Journal1.95
Chung K. Law1
Estimated H-index: 1
The state of research on developing fuel options for next-generation chemical propulsion is reviewed for aviation fuels and energetic fuels. For aviation fuels, the development is based on considerations of cost, energy security, and climate change, with Fischer–Tropsch synthetic fuels and biofuels hold potential as alternative aviation fuels. The need for basic research to develop predictive capability for the oxidative chemistry of evolving fuels in evolving engine designs is emphasized, illus...
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...
Cited By10
Newest
Published on Dec 1, 2019in Experimental Thermal and Fluid Science3.49
Haipeng Li4
Estimated H-index: 4
(University of Bremen),
Christopher D. Rosebrock5
Estimated H-index: 5
(University of Bremen)
+ 2 AuthorsLutz Mädler48
Estimated H-index: 48
(University of Bremen)
Abstract During spray combustion, the complex oxidizing atmosphere makes the direct experimental investigation of droplet evaporation and combustion challenging. Within this study, the effects of water vapor as well as the compositions of oxygen and nitrogen in the atmosphere on the single isolated droplet combustion were experimentally investigated using a high-speed digital camera. An in-house made piezoelectric droplet-on-demand generator was employed to reproducibly generate single isolated ...
Published on May 1, 2019in Combustion and Flame4.12
Álvaro Muelas (University of Zaragoza), Pilar Remacha1
Estimated H-index: 1
(University of Zaragoza),
Javier Ballester22
Estimated H-index: 22
(University of Zaragoza)
Abstract The droplet combustion characteristics of conventional heating oil, UCO biodiesel and their mixtures (10 and 20% biodiesel by volume) were examined in a free-falling droplet combustion facility designed to approach the typical temperature and oxygen conditions around individual droplets in real boiler flames. Moreover, and given the importance of avoiding effects due to gravity or convection in this type of experiments, the quite spherical soot shells recorded (infrequent event in free-...
Published on Mar 1, 2019in Journal of the Indian Institute of Science0.74
Vasudevan Raghavan13
Estimated H-index: 13
(Indian Institute of Technology Madras)
Understanding the transport processes during evaporation and combustion of isolated liquid fuel droplet is highly important in several applications involving sprays. Comprehensive numerical models assist in carrying out simulations involving interlinked transport processes in liquid and gas phases using proper interface coupling conditions. The predictions from such numerical models reveal flow, temperature and species fields, with which the evaporation, as well as combustion characteristics, ca...
Published on Oct 1, 2018in Energy5.54
Yu Zhang5
Estimated H-index: 5
(HUST: Huazhong University of Science and Technology),
Ronghua Huang11
Estimated H-index: 11
(HUST: Huazhong University of Science and Technology)
+ 4 AuthorsTian Qin1
Estimated H-index: 1
(HUST: Huazhong University of Science and Technology)
Abstract This work was aimed to study droplet combustion which was a foundation of spray combustion. Combustion characteristics of BUT00 (pure biodiesel) and BUT50 (50% n-butanol and 50% biodiesel by mass) were investigated using droplet suspension technology under 1 bar and 900 K. One flame was observed for BUT00 while two flames were observed for BUT50. The flame of BUT00 underwent successively faint luminosity, bright luminosity, soot aggregate and soot spread. The first flame of BUT50 was fa...
Published on May 1, 2018in Experimental Thermal and Fluid Science3.49
Anirudha Ambekar4
Estimated H-index: 4
(IITB: Indian Institute of Technology Bombay),
Amit Kumar Maurya1
Estimated H-index: 1
(IITB: Indian Institute of Technology Bombay),
Arindrajit Chowdhury3
Estimated H-index: 3
(IITB: Indian Institute of Technology Bombay)
Abstract An experimental study was conducted on droplet combustion of the monopropellant pure nitromethane (NM) as well as NM blended with methanol. Pure NM droplet combustion was conducted in a quiescent atmosphere of air with the droplets supported at the tip of quartz fibers under normal gravity. Additional experiments were conducted by varying the ambient oxygen mass fractions. The dependence of burning rate constant on initial droplet diameter was determined for pure NM, pure methanol, and ...
Published on Jul 1, 2016in Combustion and Flame4.12
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 Fuel5.13
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 Jun 1, 2015in Combustion and Flame4.12
Giulio Borghesi8
Estimated H-index: 8
(California Institute of Technology),
Epaminondas Mastorakos40
Estimated H-index: 40
(University of Cambridge)
Detailed numerical simulations of isolated n-heptane droplets autoignition have been conducted at pressures of 5 and 10 atm for several values of the initial ambient gas temperature. The ignition modes considered included low-, intermediate-, and high-temperature ignition. The analysis was conducted from a mixture-fraction perspective. For sufficiently low values of the ambient gas temperature, two-stage ignition was observed. Under these conditions, low-temperature reactions played an important...
Published on May 21, 2015in Energy & Fuels3.02
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 Feb 1, 2015in Renewable & Sustainable Energy Reviews10.56
Jeffrey M. Bergthorson22
Estimated H-index: 22
(McGill University),
Murray J. Thomson32
Estimated H-index: 32
(U of T: University of Toronto)
The fundamental combustion and emissions properties of advanced biofuels are reviewed, and their impact on engine performance is discussed, in order to guide the selection of optimal conversion routes for obtaining desired fuel combustion properties. Advanced biofuels from second- and third-generation feedstocks can result in significantly reduced life-cycle greenhouse-gas emissions, compared to traditional fossil fuels or first-generation biofuels from food-based feedstocks. These advanced biof...
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