The effect of elevated reactant temperatures on soot nanostructures in a coflow diffusion ethylene flame

2020 ◽  
Author(s):  
Carson Chu ◽  
Ali Naseri ◽  
Tirthankar Mitra ◽  
Mehran Dadsetan ◽  
Anton Sediako ◽  
...  
Keyword(s):  
Ethylene Flame

Numerical analysis of heat flow in oxy-ethylene flame cutting of steel plate

2016 ◽  
Vol 232 (4) ◽  
pp. 742-751 ◽  
Author(s):  
Kang-Yul Bae ◽  
Young-Soo Yang ◽  
Myung-Su Yi ◽  
Chang-Woo Park
Keyword(s):  
Numerical Simulation ◽  
Heat Flow ◽  
Heat Affected Zone ◽  
Steel Plate ◽  
Cutting Parameters ◽  
Cutting Process ◽  
Heat Sources ◽  
Power Functions ◽  
Severe Problem ◽  
Ethylene Flame

To manufacture a steel structure, in the first step, raw steel plate needs to be cut into proper sizes. Oxy-fuel flame is widely used in the cutting process due to its flexibility with respect to accessibility, plate thickness, cost, and material handling. However, the deformation caused by the cutting process frequently becomes a severe problem for the next process in the production of steel product. To decrease the deformation, the thermo-elasto-plastic behavior of the steel plate in the cutting process should be analyzed in advance. In this study, heat sources in oxy-ethylene flame cutting of steel plate were modeled first, and the heat flow in the steel plate was then analyzed by the models of the heat sources using a numerical simulation based on the finite element method. To verify the analysis by the numerical simulation including the models, a series of experiments were performed, and the temperature histories at several points on the steel plate during the cutting process were measured. Moreover, the predicted sizes of the heat-affected zone by the numerical simulations according to the variation in the cutting parameters were compared to the experimental results. The power functions of the relationship between the sizes of the heat-affected zone and cutting parameters were obtained by the recursion analysis using the correlation between the results and parameters. The results of the numerical simulation showed good agreement with those of the experiments, indicating that the proposed models of the heat sources and thermal analysis were feasible to analyze the heat flow in the steel plate during the cutting process.

Measurements of the Collisionally Quenched Lifetime of CO in Hydrocarbon Flames

1994 ◽  
Vol 48 (9) ◽  
pp. 1118-1124 ◽  
Author(s):  
Sara Agrup ◽  
Marcus Aldén
Keyword(s):  
Laser Induced Fluorescence ◽  
Polyaromatic Hydrocarbon ◽  
Time Decay ◽  
Collisional Quenching ◽  
Time Resolved ◽  
Hydrocarbon Flames ◽  
Effective Lifetime ◽  
Ethylene Flame ◽  
Oxygen Flame ◽  
Different Parts

Time-resolved laser-induced fluorescence (LIF) from CO molecules in hydrocarbon flames was studied. Collisional quenching constants were evaluated on the basis of the exponential decays. Effective lifetime in a methane/oxygen flame was observed to vary between 250 and 400 ps depending on the position within the flame, and from 400 to 600 ps in the non-sooty parts of an ethylene/air flame. Fluorescence, constituting simultaneous spatially and temporally resolved decays, was also registered from various sections along a laser beam that probed different parts of the flame. Spectral recordings revealed not only the expected CO peaks but also, in the ethylene flame, laser-induced emission from C2 Swan bands and from polyaromatic hydrocarbon (PAH) emission that affected the fluorescence time decay in the sooty part of the flame.

scholarly journals Laboratory study of the heterogeneous ice nucleation on black-carbon-containing aerosol

2019 ◽  
Vol 19 (19) ◽  
pp. 12175-12194 ◽  
Author(s):  
Leonid Nichman ◽  
Martin Wolf ◽  
Paul Davidovits ◽  
Timothy B. Onasch ◽  
Yue Zhang ◽  
...  
Keyword(s):  
Carbon Black ◽  
Black Carbon ◽  
Field Studies ◽  
Ice Nucleation ◽  
Ice Crystals ◽  
Published Data ◽  
Laboratory Measurements ◽  
Ethylene Flame ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

Abstract. Soot and black carbon (BC) particles are generated in the incomplete combustion of fossil fuels, biomass, and biofuels. These airborne particles affect air quality, human health, aerosol–cloud interactions, precipitation formation, and climate. At present, the climate effects of BC particles are not well understood. Their role in cloud formation is obscured by their chemical and physical variability and by the internal mixing states of these particles with other compounds. Ice nucleation in field studies is often difficult to interpret. Nonetheless, most field studies seem to suggest that BC particles are not efficient ice-nucleating particles (INPs). On the other hand, laboratory measurements show that in some cases, BC particles can be highly active INPs under certain conditions. By working with well-characterized BC particles, our aim is to systematically establish the factors that govern the ice nucleation activity of BC. The current study focuses on laboratory measurements of the effectiveness of BC-containing aerosol in the formation of ice crystals in temperature and ice supersaturation conditions relevant to cirrus clouds. We examine ice nucleation on BC particles under water-subsaturated cirrus cloud conditions, commonly understood as deposition-mode ice nucleation. We study a series of well-characterized commercial carbon black particles with varying morphologies and surface chemistries as well as ethylene flame-generated combustion soot. The carbon black particles used in this study are proxies for atmospherically relevant BC aerosols. These samples were characterized by electron microscopy, mass spectrometry, and optical scattering measurements. Ice nucleation activity was systematically examined in temperature and saturation conditions in the ranges of 217≤T≤235 K and 1.0≤Sice≤1.5 and 0.59≤Swater≤0.98, respectively, using a SPectrometer for Ice Nuclei (SPIN) instrument, which is a continuous-flow diffusion chamber coupled with instrumentation to measure light scattering and polarization. To study the effect of coatings on INPs, the BC-containing particles were coated with organic acids found in the atmosphere, namely stearic acid, cis-pinonic acid, and oxalic acid. The results show significant variations in ice nucleation activity as a function of size, morphology, and surface chemistry of the BC particles. The measured ice nucleation activity dependencies on temperature, supersaturation conditions, and the physicochemical properties of the BC particles are consistent with an ice nucleation mechanism of pore condensation followed by freezing. Coatings and surface oxidation modify the initial formation efficiency of pristine ice crystals on BC-containing aerosol. Depending on the BC material and the coating, both inhibition and enhancement in INP activity were observed. Our measurements at low temperatures complement published data and highlight the capability of some BC particles to nucleate ice under low ice supersaturation conditions. These results are expected to help refine theories relating to soot INP activation in the atmosphere.

A Comparative Performance Study of Soot Formation Models in Methane Elevated Pressure Non-Premixed Flames

2011 ◽  
Vol 110-116 ◽  
pp. 18-22 ◽  
Author(s):  
A. Yunardi ◽  
B. Elwina ◽  
Sylvia Novi ◽  
D. Wusnah ◽  
Bindar Yazid
Keyword(s):  
Experimental Data ◽  
Soot Formation ◽  
Elevated Pressure ◽  
Single Step ◽  
Performance Study ◽  
Ethylene Flame ◽  
Step Model ◽  
Radial Profiles ◽  
Dissipation Model ◽  
Soot Model

This paper presents results obtained from the application of a computational fluid dynamics (CFD) code Fluent 6.3 to modeling of elevated pressure methane non-premixed sooting flames. The study focuses on comparing the two soot models available in the code for the prediction of the soot level in the flames. A standard k-ε model and Eddy Dissipation model are utilized for the representation of flow field and combustion of the flame being investigated. For performance comparison study, a single step soot model of Khan and Greeves and two-step soot model proposed by Tesner are tested. The results of calculations are compared with experimental data of methane sooting flame taken from literature. The results of the study show that a combination of the standard k-ε turbulence model and eddy dissipation model is capable of producing reasonable predictions of temperature both in axial and radial profiles; although further downstream of the flame over-predicted temperature is evidence. With regard to soot model performance study, it shows that the two-step model clearly performed far better than the single-step model in predicting the soot level in ethylene flame at both axial and radial profiles. With a modification in the constant α of the soot formation equation, the two-step model was capable of producing prediction of soot level closer to experimental data. In contrast, the single-step soot model produced very poor results, leading to a significant under-prediction of soot levels in both flames. Although the Tesner’s soot model is simpler than the current available models, this model is still capable of providing reasonable agreement with experimental data, allowing its application for the purpose of design and operation of an industrial combustion system.

Detailed particle nucleation modeling in a sooting ethylene flame using a Conditional Quadrature Method of Moments (CQMOM)

2017 ◽  
Vol 36 (1) ◽  
pp. 771-779 ◽  
Author(s):  
Steffen Salenbauch ◽  
Mariano Sirignano ◽  
Daniele L. Marchisio ◽  
Martin Pollack ◽  
Andrea D'Anna ◽  
...  
Keyword(s):  
Method Of Moments ◽  
Particle Nucleation ◽  
Quadrature Method ◽  
Ethylene Flame ◽  
Quadrature Method Of Moments

scholarly journals Kinetic modeling of particle size distribution of soot in a premixed burner-stabilized stagnation ethylene flame

2015 ◽  
Vol 162 (9) ◽  
pp. 3356-3369 ◽  
Author(s):  
Chiara Saggese ◽  
Sara Ferrario ◽  
Joaquin Camacho ◽  
Alberto Cuoci ◽  
Alessio Frassoldati ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Kinetic Modeling ◽  
Ethylene Flame

Formation of small aromatic molecules in a sooting ethylene flame

1988 ◽  
Vol 72 (1) ◽  
pp. 91-109 ◽  
Author(s):  
Stephen J. Harris ◽  
Anita M. Weiner ◽  
Richard J. Blint
Keyword(s):  
Ethylene Flame ◽  
Aromatic Molecules

scholarly journals Spectroscopic observations on hydrocarbon flames in atomic oxygen

1941 ◽  
Vol 178 (974) ◽  
pp. 351-355 ◽  
Keyword(s):  
Methyl Alcohol ◽  
Atomic Hydrogen ◽  
Atomic Oxygen ◽  
Stray Light ◽  
Hydrocarbon Flames ◽  
Cool Flame ◽  
Spectroscopic Observations ◽  
Ethylene Flame ◽  
Balmer Lines ◽  
Main Discharge

Flames of hydrocarbons, burning in atomic oxygen, have been reexamined, in order to find out whether the ethylene flame bands occur in such flames. The results indicate that they are strong in benzene and acetylene, but weak and diffuse in ethylene. C 2 , CH and HO are also present. Methyl alcohol gives the HO and CH bands and also ‘cool flame’ bands rather faintly, while formaldehyde shows only the HO band at λ 3064. The ethylene flame bands are absent from the flame of benzene burning in atomic hydrogen, which yields only C 2 and CH bands. The Balmer lines also appear, however, due to stray light from the main discharge.

Experimental and computational study of soot evolution in a turbulent nonpremixed bluff body ethylene flame

2013 ◽  
Vol 160 (7) ◽  
pp. 1298-1309 ◽  
Author(s):  
Michael E. Mueller ◽  
Qing N. Chan ◽  
Nader H. Qamar ◽  
Bassam B. Dally ◽  
Heinz Pitsch ◽  
...  
Keyword(s):  
Bluff Body ◽  
Computational Study ◽  
Ethylene Flame ◽  
Turbulent Nonpremixed

Soot particle inception and O2 profiles in a premixed ethylene flame

1986 ◽  
Vol 66 (2) ◽  
pp. 211-214 ◽  
Author(s):  
Stephen J. Harris
Keyword(s):  
Soot Particle ◽  
Ethylene Flame
Sign in / Sign up

Export Citation Format

Share Document