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Flame extinction and low-temperature combustion of isolated fuel droplets of n-alkanes

Published on Jan 1, 2017
· DOI :10.1016/j.proci.2016.08.019
Alberto Cuoci27
Estimated H-index: 27
(Polytechnic University of Milan),
Abd Essamade Saufi1
Estimated H-index: 1
(Polytechnic University of Milan)
+ 3 AuthorsT. Faravelli43
Estimated H-index: 43
(Polytechnic University of Milan)
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Abstract
Abstract A recent set of experiments carried out onboard the International Space Station (ISS) have shown that large n-alkane droplets, after the radiative extinction of the visible flame, can burn quasi-steadily in a low-temperature regime, up to a diffusive extinction accompanied by the formation of a vapor cloud. The experiments have also demonstrated that small droplets are unable to exhibit radiative extinction, but instead burn to completion or disruptively extinguish. In this work, we applied a mathematical model able to reproduce the experimental data in terms of vaporization rates, standoff ratios, extinction diameters. A detailed kinetic mechanism (with ∼450 species and ∼17,000 reactions) was taken into account, in order to correctly reproduce the low-temperature combustion regime. The role of several parameters (initial diameter of the droplet, composition of the gaseous environment, and pressure) on the extinction of the hot-temperature flames was numerically investigated. Predictions are found in good agreement with experimental measurements, showing that only droplets with an initial diameter larger than a critical diameter undergo radiative extinction. A linear relationship between the squared critical diameter and the molar fraction of oxygen in the atmosphere was found and demonstrated on the basis of scaling arguments.
  • References (22)
  • Citations (7)
Cite
References22
Newest
Published on Sep 1, 2016in Combustion and Flame4.12
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 May 1, 2015in Combustion and Flame4.12
Vedha Nayagam4
Estimated H-index: 4
(Case Western Reserve University),
Daniel L. Dietrich13
Estimated H-index: 13
(Glenn Research Center)
+ 1 AuthorsForman A. Williams48
Estimated H-index: 48
(UCSD: University of California, San Diego)
Abstract Recent droplet-combustion experiments onboard the International Space Station (ISS) have revealed that large n-alkane droplets, following radiative extinction of the visible flame, can continue to burn quasi-steadily in a low-temperature regime, characterized by negative-temperature-coefficient (NTC) chemistry. In this study we report experimental observations of n-heptane, n-octane, and n-decane droplets of varying initial size burning in oxygen/nitrogen, oxygen/nitrogen/carbon dioxide...
Published on Jan 1, 2015
Alberto Cuoci27
Estimated H-index: 27
(Polytechnic University of Milan),
Alessio Frassoldati34
Estimated H-index: 34
(Polytechnic University of Milan)
+ 1 AuthorsE. Ranzi49
Estimated H-index: 49
(Polytechnic University of Milan)
Abstract In this work we present and apply a mathematical model to simulate the auto-ignition of isolated fuel droplets burning in microgravity conditions. The aim is to demonstrate the fundamental role of the low-temperature mechanisms on the auto-ignition process and to show that several experimental observations cannot be explained without considering the formation of cool-flames around the burning droplet. Thus, in order to better clarify the importance of the low-temperature chemistry, a de...
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 Nov 20, 2014in Energy & Fuels3.02
Matteo Pelucchi7
Estimated H-index: 7
,
Mattia Bissoli3
Estimated H-index: 3
+ 5 AuthorsAlessandro Stagni8
Estimated H-index: 8
The low- and high-temperature oxidation mechanisms of n-heptane have been extensively studied in recent and past literature because of its importance as a primary reference fuel. Recent advanced analytical methods allowed for the identification of several intermediate oxygenated species at very low-temperature conditions in jet-stirred reactors. On these bases, new classes of successive reactions involving hydroperoxide species, already discussed for propane and n-butane oxidation, were included...
Published on Oct 1, 2014in Microgravity Science and Technology1.97
Daniel L. Dietrich13
Estimated H-index: 13
(Glenn Research Center),
Vedha Nayagam4
Estimated H-index: 4
(Case Western Reserve University)
+ 9 AuthorsYu Cheng Liu10
Estimated H-index: 10
(Cornell University)
This paper summarizes the first results from isolated droplet combustion experiments performed on the International Space Station (ISS). The long durations of microgravity provided in the ISS enable the measurement of droplet and flame histories over an unprecedented range of conditions. The first experiments were with heptane and methanol as fuels, initial droplet droplet diameters between 1.5 and 5.0 m m, ambient oxygen mole fractions between 0.1 and 0.4, ambient pressures between 0.7 and 3.0 ...
Published on Sep 3, 2014in Combustion Theory and Modelling1.65
Guenter Paczko2
Estimated H-index: 2
(RWTH Aachen University),
N. Peters56
Estimated H-index: 56
(RWTH Aachen University)
+ 1 AuthorsForman A. Williams48
Estimated H-index: 48
(UCSD: University of California, San Diego)
Experiments on the combustion of large n-heptane droplets, performed by the National Aeronautics and Space Administration in the International Space Station, revealed a second stage of continued quasi-steady burning, supported by low-temperature chemistry, that follows radiative extinction of the first stage of burning, which is supported by normal hot-flame chemistry. The second stage of combustion experienced diffusive extinction, after which a large vapour cloud was observed to form around th...
Published on Jun 4, 2014in Industrial & Engineering Chemistry Research3.38
Alessandro Stagni8
Estimated H-index: 8
,
Alberto Cuoci27
Estimated H-index: 27
+ 2 AuthorsE. Ranzi49
Estimated H-index: 49
When it comes to handling large hydrocarbon molecules and describing the pyrolysis and combustion behavior of complex mixtures, the potential and limitations of detailed chemistry require a careful investigation. Indeed, as they involve a large number of species and reactions, detailed kinetic mechanisms often make the model predictions computationally expensive, thus strongly restricting their potential. Therefore, the automatic generation of detailed mechanisms with several thousands of molecu...
Published on Feb 1, 2014in Combustion and Flame4.12
Tanvir Farouk17
Estimated H-index: 17
(USC: University of South Carolina),
Frederick L. Dryer66
Estimated H-index: 66
(Princeton University)
Abstract Recent experimentally observed two stage combustion of n -heptane droplets in microgravity is numerically studied. The simulations are conducted with detailed chemistry and transport in order to obtain insight into the features controlling the low temperature second stage burn. Predictions show that the second stage combustion occurs as a result of chemical kinetics associated with classical premixed “ Cool Flame ” phenomena. In contrast to the kinetic interactions responsible for premi...
Published on Oct 17, 2013in Energy & Fuels3.02
Chungen Yin23
Estimated H-index: 23
Radiation is the principal mode of heat transfer in utility boiler furnaces. Models for radiative properties play a vital role in reliable simulations of utility boilers and simulation-based design and optimization. The weighted sum of gray gases model (WSGGM) is one of the most widely used models in computational fluid dynamics (CFD) simulation of air-fuel combustion processes. It represents a reasonable compromise between an oversimplified gray gas model and a comprehensive approach addressing...
Cited By7
Newest
Published on Mar 21, 2019in Combustion Theory and Modelling1.65
Forman A. Williams48
Estimated H-index: 48
(UCSD: University of California, San Diego),
Vedha Nayagam13
Estimated H-index: 13
(Case Western Reserve University),
Vedha Nayagam4
Estimated H-index: 4
(Case Western Reserve University)
Published on Jul 1, 2019in Progress in Energy and Combustion Science26.47
Zhandong Wang21
Estimated H-index: 21
(KAUST: King Abdullah University of Science and Technology),
Olivier Herbinet32
Estimated H-index: 32
(University of Lorraine)
+ 1 AuthorsFrédérique Battin-Leclerc45
Estimated H-index: 45
(University of Lorraine)
Abstract The aim of this paper is to review recent progress in detection and quantification of hydroperoxides, and to understand their reaction kinetics in combustion environments. Hydroperoxides, characterized by an OOH group, are ubiquitous in the atmospheric oxidation of volatile organic compounds (∼300 K), and in the liquid and gas phase oxidation of fuel components at elevated temperatures (∼400–1000 K). They are responsible for two-stage fuel ignition in internal combustion engines and the...
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 Mar 1, 2019in International Journal of Heat and Mass Transfer4.35
A.E. Saufi (Leonardo), Alessio Frassoldati34
Estimated H-index: 34
(Leonardo)
+ 1 AuthorsAlberto Cuoci27
Estimated H-index: 27
(Leonardo)
Abstract This paper aims at presenting the DropletSMOKE++ solver, a comprehensive multidimensional computational framework for the evaporation of fuel droplets, under the influence of a gravity field and an external fluid flow. The Volume Of Fluid (VOF) methodology is adopted to dynamically track the interface, coupled with the solution of energy and species equations. The evaporation rate is directly evaluated based on the vapor concentration gradient at the phase boundary, with no need of semi...
Published on Mar 1, 2018in Combustion and Flame4.12
Alessandro Stagni8
Estimated H-index: 8
(Polytechnic University of Milan),
Alberto Cuoci27
Estimated H-index: 27
(Polytechnic University of Milan)
+ 2 AuthorsT. Faravelli43
Estimated H-index: 43
(Polytechnic University of Milan)
Abstract The use of isolated droplets as idealized systems is an established practice to get an insight on the physics of combustion, and an optimal test field to verify physical submodels. In this context, this work examines the dynamics of soot formation from the combustion of hydrocarbon liquid fuels in such conditions. A detailed, heterogeneous kinetic mechanism, describing aerosol and particle behavior through a discrete sectional approach is incorporated. The developed 1-dimensional model ...
Published on Feb 1, 2018in Combustion and Flame4.12
Alessandro Stagni8
Estimated H-index: 8
(Polytechnic University of Milan),
Davide Brignoli (Polytechnic University of Milan)+ 4 AuthorsT. Faravelli43
Estimated H-index: 43
(Polytechnic University of Milan)
Abstract The continuous research towards novel combustion technologies, operating at high temperatures and pressures, has recently raised the question of the influence of low temperature chemistry in such conditions. As a first step in identifying the potentially critical conditions where low-temperature oxidation might play a major role, this theoretical study investigates the steady-state flame evolution of 1-dimensional, partially-premixed counterflow diffusion flames. To this purpose, n -hep...
Zhandong Wang21
Estimated H-index: 21
(KAUST: King Abdullah University of Science and Technology),
Denisia M. Popolan-Vaida9
Estimated H-index: 9
(University of California, Berkeley)
+ 10 AuthorsNils Hansen34
Estimated H-index: 34
(SNL: Sandia National Laboratories)
Decades of research on the autooxidation of organic compounds have provided fundamental and practical insights into these processes; however, the structure of many key autooxidation intermediates and the reactions leading to their formation still remain unclear. This work provides additional experimental evidence that highly oxygenated intermediates with one or more hydroperoxy groups are prevalent in the autooxidation of various oxygenated (e.g., alcohol, aldehyde, keto compounds, ether, and es...