Match!

Microgravity n-Heptane Droplet Combustion in Oxygen-Helium Mixtures at Atmospheric Pressure

Published on Jan 1, 1998in AIAA Journal1.95
· DOI :10.2514/2.557
Vedha Nayagam13
Estimated H-index: 13
,
John B. Haggard5
Estimated H-index: 5
+ 4 AuthorsForman A. Williams48
Estimated H-index: 48
Cite
Abstract
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 sizes ranged from about 2 to 4 mm. The results demonstrated both radiative and diffusive flame extinction during burning, whereas droplet surface regression followed the d-square law. The full range of possible droplet-burning behaviors was thus observed. The results provide information for testing future theoretical and computational predictions of burning rates, soot and flame characteristics, and extinction conditions.
  • References (56)
  • Citations (68)
Cite
References56
Newest
Published on Jul 1, 1999in Combustion Science and Technology1.56
Seungwookbaek30
Estimated H-index: 30
(KAIST),
Jae Hyun Park8
Estimated H-index: 8
(KAIST),
Chang Eun Choi3
Estimated H-index: 3
(KAIST)
Single droplet combustion processes including heating, evaporation, burning, soot formation and flame radiation were theoretically investigated by adopting nongray gas radiation model for the radiative transfer equation (RTE). n-Heptane was chosen as a fuel in the numerical calculation and the results were compared with the experimental data available in the literature. The discrete ordinate method (DOM) was employed to solve the radiative transfer equation and the weighted sum of gray gases mod...
Published on Jan 1, 1998
Paul D. Ronney34
Estimated H-index: 34
(SC: University of Southern California)
A review of research on the effects of gravity on combustion processes is presented, with an emphasis on a discussion of the ways in which reduced-gravity experiments and modeling has led to new understanding. Comparison of time scales shows that the removal of buoyancy-induced convection leads to manifestations of other transport mechanisms, notably radiative heat transfer and diffusional processes such as Lewis number effects. Examples from premixed-gas combustion, non-premixed gas-jet flames,...
Published on Jan 1, 1998
Anthony J. Marchese23
Estimated H-index: 23
(Princeton University),
Frederick L. Dryer66
Estimated H-index: 66
(Princeton University),
R.O. Colantonio4
Estimated H-index: 4
The results from methanol/water droplet combustion experiments conducted on two separate spacebased investigations are analyzed and compared against the predictions of a detailed numerical model. These two investigations (Fiber Supported Droplet Combustion Investigations 1 and 2) were conducted aboard Space Shuttle Columbia missions STS-73 and STS-94 in November 1995 and July 1997, respectively. In these experiments, pure methanol droplets and methanol/water droplets of 2–7 mm were suspended on ...
Published on May 1, 1997in Combustion Science and Technology1.56
Maozhao Xie1
Estimated H-index: 1
(DUT: Dalian University of Technology),
Xiaohong Liang1
Estimated H-index: 1
(DUT: Dalian University of Technology)
Abstract A two-dimensional axisymmetrical numerical model for combustion of a carbon packed bed is presented. The model is set up by coupling a gas-particle two-phase flow inside the bed to a stagnation point flow in the boundary layer on the bed surface. The PISO algorithm is employed for the solution. Computations have been performed for the two limiting cases of a frozen and of an equilibrium flow as well as for finite homogeneous reactions rates. The combustion rates of the packing for vario...
Published on May 1, 1997in Combustion and Flame4.12
Fernando F. Fachini5
Estimated H-index: 5
(INPE: National Institute for Space Research),
Amable Liñán24
Estimated H-index: 24
(UPM: Technical University of Madrid)
We discuss the transient effects of mass and energy accumulation processes and of an applied acoustic field interaction on the droplet ignition phenomenon. In order to observe simultaneously the influence of those processes on the ignition, we assume that the chemical reaction occurs in the droplet unsteady far field, where the transient accumulation processes and the acoustic field are as important as the other processes (i.e., the conduction process and the chemical reaction). We also consider...
Published on May 1, 1997in Combustion Science and Technology1.56
M. L Rightley1
Estimated H-index: 1
(UCSD: University of California, San Diego),
Forman A. Williams48
Estimated H-index: 48
(UCSD: University of California, San Diego)
Abstract Computational results are reported for structures of laminar counterflow diffusion flames between carbon monoxide and air, initially at room temperature and pressure from 1 to 100 atm, with total hydrogen-atom mole fractions in the system ranging from zero to about 0.02. All strain rates considered are within a factor of ten of the critical extinction strain rate. This critical strain rate is calculated as a function of pressure and of hydrogen content and is shown to lie below measured...
Published on Mar 1, 1997in Combustion and Flame4.12
K. Seshadri3
Estimated H-index: 3
(RWTH Aachen University),
M. Bollig3
Estimated H-index: 3
(RWTH Aachen University),
N. Peters56
Estimated H-index: 56
(RWTH Aachen University)
Abstract Numerical calculations and rate-ratio asymptotic analysis are performed to obtain the structure and burning velocities of premixed heptane flames. The numerical calculations are performed using a detailed chemical-kinetic mechanism comprising 257 elementary reactions, a skeletal chemical-kinetic mechanism comprising 34 elementary reactions and a reduced chemical-kinetic mechanism made up of six overall steps. The reduced chemical-kinetic mechanism is deduced from the skeletal mechanism....
Published on Mar 1, 1997in Combustion Science and Technology1.56
Anthony J. Marchese23
Estimated H-index: 23
(Princeton University),
Frederick L. Dryer66
Estimated H-index: 66
(Princeton University)
The effect or radiative heat loss from isolated droplet flames is usually assumed to be negligible. For the small droplet sizes studied in most isolated droplet combustion experiments conducted to dale (< 1.0 mm), this assumption has been shown to be reasonable. For example, by neglecting radiation, a detailed numerical model accurately predicts the burning rate, flame position and extinction diameter for 1 millimeter-sized methanol/waler droplets. However, recent space-based 3 to 5 millimeter m...
Published on Jan 1, 1997in Combustion Science and Technology1.56
T.J. Held4
Estimated H-index: 4
(Princeton University),
Anthony J. Marchese23
Estimated H-index: 23
(Princeton University),
Frederick L. Dryer66
Estimated H-index: 66
(Princeton University)
A new semi-empirical mechanism for n-heptane oxidation and pyrolysis has been developed and validated against several independent data sets, including new flow reactor experiments. Previous semi-empirical chemical kinetic mechanisms assumed that a generic n-alkyl radical, formed by abstraction of an H-atom from the parent fuel, thermally decomposes into a fixed ratio of methyl and propene. While such an approach has been reasonably successful in predicting premixed, laminar flame speeds, the mec...
Published on Feb 1, 1996
Robert Klimek2
Estimated H-index: 2
,
Ted Wright2
Estimated H-index: 2
,
Robert S. Sielken1
Estimated H-index: 1
Cited By68
Newest
Published on 2019in Progress in Energy and Combustion Science26.47
Yiguang Ju54
Estimated H-index: 54
(Princeton University),
Christopher B. Reuter7
Estimated H-index: 7
(Princeton University)
+ 2 AuthorsSang Hee Won3
Estimated H-index: 3
(USC: University of South Carolina)
Abstract Cool flames play a critical role in ignition timing, burning rate, burning limits, engine knocking, and emissions in conventional and advanced combustion engines. This paper provides an overview of the recent progress in experimental and computational studies of cool flames. First, a brief review of low-temperature chemistry and classical studies of cool flames is presented. Next, the recent experimental and computational findings of cool flames in microchannels, microgravity droplet co...
Published on Jul 1, 2019in Combustion and Flame4.12
Vedha Nayagam13
Estimated H-index: 13
,
Daniel L. Dietrich13
Estimated H-index: 13
,
Forman A. Williams48
Estimated H-index: 48
Abstract A scaling analysis of burner-supported spherical-diffusion-flame extinction brought about by radiative heat loss is presented. The results are compared against earlier microgravity experimental data and unsteady numerical computations with detailed chemistry available in the literature, for normal and inverse flames. The flame diameter at extinction is shown to correlate well with the present model, in which the extinction radius scales with one-third power of gas flow rate times reacta...
Published on Apr 1, 2019in International Journal of Heat and Mass Transfer4.35
René Spencer Chatwell (Technical University of Berlin), Matthias Heinen2
Estimated H-index: 2
(Technical University of Berlin),
Jadran Vrabec33
Estimated H-index: 33
(Technical University of Berlin)
Abstract An analytical solution of a model fluid’s time behavior, known as the Stefan problem, is presented. A scenario is investigated in which a planar two-component liquid film is continuously evaporating into a thermodynamically non-ideal vapor phase. Evaporation is initiated and maintained by a spatial chemical potential gradient, while its rate is limited by the components’ diffusion fluxes across the vapor-liquid interface. Local thermodynamic equilibrium is found to be present throughout...
Published on Aug 1, 2018in 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 Experimental observations are presented concerning radiative extinction of large n-alkane droplets in diluent-substituted environments at moderately varied pressures in microgravity onboard the International Space Station. The fuels considered are n-heptane, n-octane, and n-decane with carbon dioxide, helium, and xenon used as inerts, replacing nitrogen as diluents at varying amounts. It is shown that a simple scaling analysis, based on the assumptions that radiative extinction occurs w...
Published on Jun 1, 2018in Combustion and Flame4.12
A. Markan1
Estimated H-index: 1
(UMD: University of Maryland, College Park),
Peter B. Sunderland19
Estimated H-index: 19
(UMD: University of Maryland, College Park)
+ 3 AuthorsHoward R. Baum6
Estimated H-index: 6
(UMD: University of Maryland, College Park)
Abstract The Burning Rate Emulator (BRE) is a gas-fueled burner that emulates the burning of real condensed phase fuels. This is accomplished by matching four fundamental properties: heat of gasification, heat of combustion, surface vaporization temperature, and smoke point. Previous research has confirmed the BRE technique in normal gravity. The aim of the current study is to establish immediate sustained burning in a calm microgravity environment. This paper presents 49 BRE tests at NASA Glenn...
Published on Mar 4, 2017in Combustion Science and Technology1.56
Daniel L. Dietrich13
Estimated H-index: 13
(Glenn Research Center),
R. Calabria1
Estimated H-index: 1
+ 2 AuthorsForman A. Williams48
Estimated H-index: 48
(UCSD: University of California, San Diego)
ABSTRACTThis article presents the results of experiments conducted aboard the International Space Station involving the combustion of large bi-component droplets of decane and hexanol (50/50 by volume) in air ambients with ambient pressures between 0.05 and 0.30 MPa. The experiments showed the presence of sustained low-temperature or cool-flame burning following radiative extinction of large droplets at ambient pressures greater than or equal to 0.10 MPa. The droplet diameters at cool-flame exti...
Published on Feb 1, 2017in Microgravity Science and Technology1.97
Shreyash Gulati1
Estimated H-index: 1
(RPI: Rensselaer Polytechnic Institute),
Aditya Raghunandan3
Estimated H-index: 3
(RPI: Rensselaer Polytechnic Institute)
+ 2 AuthorsAmir Hirsa19
Estimated H-index: 19
(RPI: Rensselaer Polytechnic Institute)
Microgravity is potentially a powerful tool for investigating processes that are sensitive to the presence of solid walls, since fluid containment can be achieved by surface tension. One such process is the transformation of protein in solution into amyloid fibrils; these are protein aggregates associated with neurodegenerative diseases such as Alzheimer’s and Parkinson’s. In addition to solid walls, experiments with gravity are also subject to influences from sedimentation of aggregates and buo...
Published on Jan 1, 2017
Tanvir I. Farouk4
Estimated H-index: 4
(USC: University of South Carolina),
Daniel L. Dietrich13
Estimated H-index: 13
(Glenn Research Center)
+ 1 AuthorsFrederick L. Dryer4
Estimated H-index: 4
(Princeton University)
Abstract Observations of “ Cool Flame ” burning for large diameter isolated droplets on board the International Space Station have stimulated interest in combustion initiation/generation of non-premixed combustion modes. For a number of n -alkane fuels at large initial droplet diameters, the initiation process was observed to first establish a hot flame condition that radiatively extinguished, followed by a quasi-steady, “ Cool Flame ” droplet burning mode. However, recent large diameter n -deca...
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 Journal of Mechanical Science and Technology1.22
Hyun Kyu Suh18
Estimated H-index: 18
(KNU: Kongju National University)
This study was conducted to improve the theoretical prediction of the burning characteristics of an n-heptane droplet by comparing them with experimental results. To achieve this, numerical approaches were conducted by assuming that the droplet combustion can be described by both quasi-steady behavior for the region between the droplet surface and the flame interface, and transient behavior for the region between the flame interface and ambient surrounding. Comparisons were considered for drople...
View next paperDroplet Combustion Experiments in Spacelab