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Tethered methanol droplet combustion in carbon-dioxide enriched environment under microgravity conditions

Published on Jan 1, 2012in Combustion and Flame 4.12
· DOI :10.1016/j.combustflame.2011.06.014
Tanvir Farouk17
Estimated H-index: 17
(Princeton University),
Frederick L. Dryer66
Estimated H-index: 66
(Princeton University)
Cite
Abstract
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 increases the burning rate significantly and hence decreases the extinction diameter. The simulations further show that the extinction diameter depends on both the initial droplet diameter and the ambient concentration of carbon dioxide. Increasing the droplet diameter and ambient carbon dioxide concentration both of them lead to a decrease in the burning rate and increase in the extinction diameter. The influence of ambient carbon dioxide concentration on extinction shows a sharp transition in extinction for larger size droplets ( d o  > 1.5 mm) due to a change in the mode of extinction from diffusive to radiative control. In addition predictions from the numerical model is compared against a recently developed simplified theoretical model for predicting extinction diameter for methanol droplets, where the presence and heat transfer contribution of the tether is not taken into account implicitly. The numerical results suggest some limitation in the theoretical modeling assumptions for favorable comparisons with the experimental data.
  • References (25)
  • Citations (21)
Cite
References25
Newest
Published on Jan 1, 2011
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)
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 ...
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 Jan 1, 2010in Combustion and Flame 4.12
Vedha Nayagam13
Estimated H-index: 13
(Glenn Research Center)
Abstract Recently, Aharon and Shaw developed a simplified analytical expression to predict quasi-steady flame stand-off ratios for alkane fuels. Their analysis is strictly valid only for alkane-type fuels where there is no reabsorption of flame generated species back into the droplet. In this note we show that Aharon and Shaw’s analysis can be extended to methanol droplet combustion where water generated at the flame-sheet is absorbed back into the droplet. The model predictions are shown to com...
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 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
Zheng Chen30
Estimated H-index: 30
(Princeton University),
Xiao Qin7
Estimated H-index: 7
(Princeton University)
+ 2 AuthorsFengshan Liu1
Estimated H-index: 1
(National Research Council)
Abstract The effects of spectral radiation absorption on the flame speed at normal and elevated pressures were experimentally and numerically investigated using the CO 2 diluted outwardly propagating CH 4 –O 2 –He flames. Experimentally, the laminar burning velocities of CH 4 –O 2 –He–CO 2 mixtures at both normal and elevated pressures (up to 5 atm) were measured by using a pressure-release type spherical bomb. The results showed that radiation absorption with CO 2 addition increases the flame s...
Published on Nov 1, 2005in Combustion Theory and Modelling 1.65
Daniel L. Dietrich13
Estimated H-index: 13
(Glenn Research Center),
Peter M. Struk11
Estimated H-index: 11
(Glenn Research Center)
+ 1 AuthorsGuangwen Xu8
Estimated H-index: 8
This paper presents experimental data on single droplet combustion of decane in microgravity and compares the results to a numerical model. The primary independent experiment variables are the ambient pressure and oxygen mole fraction, pressure, droplet size (over a relatively small range) and ignition energy. The droplet history (D2 history) is non-linear with the burning rate constant increasing throughout the test. The average burning rate constant, consistent with classical theory, increased...
Published on May 1, 2005in Combustion and Flame 4.12
Masato Mikami14
Estimated H-index: 14
(Yamaguchi University),
Hiroshi Oyagi3
Estimated H-index: 3
(Yamaguchi University)
+ 3 AuthorsShinichi Yoda21
Estimated H-index: 21
(JAXA: Japan Aerospace Exploration Agency)
Abstract A new droplet-array generation technique achieved high quality and high reliability in microgravity experiments on multiple-droplet combustion. Each fuel droplet formed at the intersection of fine, X-shaped SiC fibers when liquid fuel was supplied through a fine glass tube. We aligned several sets of these X-shaped fibers and their corresponding fine glass tubes to form a droplet array. All the droplets in the array were simultaneously generated in a short time. In flame-spread experime...
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...
Cited By21
Newest
Published on Nov 1, 2019in Fuel 5.13
Anand Sankaranarayanan (IITB: Indian Institute of Technology Bombay), Sohan Lal3
Estimated H-index: 3
(IITB: Indian Institute of Technology Bombay)
+ 3 AuthorsNeeraj Kumbhakarna5
Estimated H-index: 5
(IITB: Indian Institute of Technology Bombay)
Abstract Droplet combustion behaviour of an RP-1 surrogate fuel (RP-1-s), its constituents, and two novel energetic fuels – 1,3-bishomocubane dimer (BHCD) and bis(nitratomethyl)-1-3-bishomocubane (DNMBHC) was investigated. The novel energetic fuels, envisioned as potential fuels in rocket propulsion were observed to be completely miscible with RP-1-s. Experiments were also conducted on a 10% w/w mixture of BHCD in RP-1-s (BHCD10) and a 10% w/w mixture of DNMBHC in RP-1-s (DNMBHC10). Tests were c...
Published on Mar 1, 2019in Journal of the Indian Institute of Science 0.74
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 Mar 1, 2018in Applied Thermal Engineering 4.03
Yu Zhang5
Estimated H-index: 5
(HUST: Huazhong University of Science and Technology),
Yuhan Huang8
Estimated H-index: 8
(HUST: Huazhong University of Science and Technology)
+ 4 AuthorsZhaowen Wang6
Estimated H-index: 6
(HUST: Huazhong University of Science and Technology)
Abstract A new model was developed to investigate the puffing process of a butanol-hexadecane droplet. The puffing model took into account all the key processes, including the surface evaporation, bubble formation, bubble growth and bubble breakup. The Rayleigh equation was modified to simulate the bubble growth inside a small droplet. The sub-models for surface evaporation and bubble growth were firstly verified against the previous experimental data. Then the droplet puffing experiments of but...
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 Jan 2, 2015in Combustion Science and Technology 1.56
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. ...
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...
Published on Jan 1, 2015
Tanvir Farouk17
Estimated H-index: 17
(USC: University of South Carolina),
Michael C. Hicks8
Estimated H-index: 8
(Glenn Research Center),
Frederick L. Dryer66
Estimated H-index: 66
(Princeton University)
Abstract Recently, large diameter, isolated n -heptane droplet experiments under microgravity conditions (aboard the International Space Station) exhibited “ Cool Flame ” burning behavior, resulting from a heat loss mechanism that extinguishes hot combustion and a transition into a sustained, low temperature second stage combustion. In atmospheric pressure air, a single combustion mode transition to “ Cool Flame ” burning is followed by diffusive extinction. But with increasing pressure, multipl...
Published on Jan 1, 2015
Hidefumi Kataoka2
Estimated H-index: 2
(OPU: Osaka Prefecture University),
H. Yamashita1
Estimated H-index: 1
(OPU: Osaka Prefecture University)
+ 5 AuthorsToshikazu Kadota15
Estimated H-index: 15
(OPU: Osaka Prefecture University)
Abstract Autoignition behavior of spherical clusters of pure droplets was experimentally examined near the ignition limit. The fuel with the melting points little above room temperatures was selected as the test fuel. The three-dimensional droplet clusters having hexagonal closest packing structure were selected as the test clusters, which consisted of a center droplet and surrounding twelve droplets (thirteen droplets in total). The initial diameters of the droplets were much reduced from the a...
Published on Jan 1, 2015
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)
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 o...
Published on Jan 1, 2015
Yu Cheng Liu10
Estimated H-index: 10
(Cornell University),
Yuhao Xu7
Estimated H-index: 7
(Cornell University)
+ 1 AuthorsMichael C. Hicks8
Estimated H-index: 8
(Glenn Research Center)
Abstract This study reports experimental evidence of gas phase micro-convection induced by support fibers used in droplet combustion experimentation. Soot aggregates formed during combustion of n-octane and n-decane droplets (initial diameters ranging from 0.5 mm to 5 mm) provide natural seeds to reveal the thermal and flow asymmetries involved. The experiments are carried out in an environment that reduces the influence of forced and buoyant convection for both free-floating (unsupported) and f...