Soot Formation in Annular Non-premixed Laminar Flames of Methane-air at Pressures of 0.1 to 4.0 MPa [microform]

Soot Formation in Annular Non-premixed Laminar Flames of Methane-air at Pressures of 0.1 to 4.0 MPa [microform] PDF Author: Kevin Austen Thomson
Publisher: Library and Archives Canada = Bibliothèque et Archives Canada
ISBN: 9780494029565
Category :
Languages : en
Pages : 592

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Soot Formation in Annular Non-premixed Laminar Flames of Methane-air at Pressures of 0.1 to 4.0 MPa [microform]

Soot Formation in Annular Non-premixed Laminar Flames of Methane-air at Pressures of 0.1 to 4.0 MPa [microform] PDF Author: Kevin Austen Thomson
Publisher: Library and Archives Canada = Bibliothèque et Archives Canada
ISBN: 9780494029565
Category :
Languages : en
Pages : 592

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Soot Formation in Non-premixed Laminar Flames at Subcritical and Supercritical Pressures

Soot Formation in Non-premixed Laminar Flames at Subcritical and Supercritical Pressures PDF Author: Hyun Il Joo
Publisher:
ISBN:
Category :
Languages : en
Pages :

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An experimental study was conducted using axisymmetric co-flow laminar diffusion flames of methane-air, methane-oxygen and ethylene-air to examine the effect of pressure on soot formation and the structure of the temperature field. A liquid fuel burner was designed and built to observe the sooting behavior of methanol-air and n-heptane-air laminar diffusion flames at elevated pressures up to 50 atm. A non-intrusive, line-of-sight spectral soot emission (SSE) diagnostic technique was used to determine the temperature and the soot volume fraction of methane-air flames up to 60 atm, methane-oxygen flames up to 90 atm and ethylene-air flames up to 35 atm. The physical flame structure of the methane-air and methane-oxygen diffusion flames were characterized over the pressure range of 10 to 100 atm and up to 35 atm for ethylene-air flames. The flame height, marked by the visible soot radiation emission, remained relatively constant for methane-air and ethylene-air flames over their respected pressure ranges, while the visible flame height for the methane-oxygen flames was reduced by over 50 % between 10 and 100 atm. During methane-air experiments, observations of anomalous occurrence of liquid material formation at 60 atm and above were recorded. The maximum conversion of the carbon in the fuel to soot exhibited a strong power-law dependence on pressure. At pressures 10 to 30 atm, the pressure exponent is approximately 0.73 for methane-air flames. At higher pressures, between 30 and 60 atm, the pressure exponent is approximately 0.33. The maximum fuel carbon conversion to soot is 12.6 % at 60 atm. For methane-oxygen flames, the pressure exponent is approximately 1.2 for pressures between 10 and 40 atm. At pressures between 50 and 70 atm, the pressure exponent is about -3.8 and approximately -12 for 70 to 90 atm. The maximum fuel carbon conversion to soot is 2 % at 40 atm. For ethylene-air flames, the pressure exponent is approximately 1.4 between 10 and 30 atm. The maximum carbon conversion to soot is approximately 6.5 % at 30 atm and remained constant at higher pressures.

Soot Formation in Non-premixed Laminar Flames at Subcritical and Supercritical Pressures

Soot Formation in Non-premixed Laminar Flames at Subcritical and Supercritical Pressures PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
An experimental study was conducted using axisymmetric co-flow laminar diffusion flames of methane-air, methane-oxygen and ethylene-air to examine the effect of pressure on soot formation and the structure of the temperature field. A liquid fuel burner was designed and built to observe the sooting behavior of methanol-air and n-heptane-air laminar diffusion flames at elevated pressures up to 50 atm. A non-intrusive, line-of-sight spectral soot emission (SSE) diagnostic technique was used to determine the temperature and the soot volume fraction of methane-air flames up to 60 atm, methane-oxygen flames up to 90 atm and ethylene-air flames up to 35 atm. The physical flame structure of the methane-air and methane-oxygen diffusion flames were characterized over the pressure range of 10 to 100 atm and up to 35 atm for ethylene-air flames. The flame height, marked by the visible soot radiation emission, remained relatively constant for methane-air and ethylene-air flames over their respected pressure ranges, while the visible flame height for the methane-oxygen flames was reduced by over 50 % between 10 and 100 atm. During methane-air experiments, observations of anomalous occurrence of liquid material formation at 60 atm and above were recorded. The maximum conversion of the carbon in the fuel to soot exhibited a strong power-law dependence on pressure. At pressures 10 to 30 atm, the pressure exponent is approximately 0.73 for methane-air flames. At higher pressures, between 30 and 60 atm, the pressure exponent is approximately 0.33. The maximum fuel carbon conversion to soot is 12.6 % at 60 atm. For methane-oxygen flames, the pressure exponent is approximately 1.2 for pressures between 10 and 40 atm. At pressures between 50 and 70 atm, the pressure exponent is about -3.8 and approximately -12 for 70 to 90 atm. The maximum fuel carbon conversion to soot is 2 % at 40 atm. For ethylene-air flames, the pressure exponent is approximately 1.4 between 10 and 30 atm. The maximu.

High Pressure Soot Formation in Non-smoking Methane-air Laminar Diffusion Flames from 1.5 MPa to 6.0 MPa

High Pressure Soot Formation in Non-smoking Methane-air Laminar Diffusion Flames from 1.5 MPa to 6.0 MPa PDF Author: Marie Emma Vaillancourt
Publisher:
ISBN: 9780494210178
Category : Combustion
Languages : en
Pages : 190

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Book Description
Measurements of soot concentration, flame temperature and flame geometry have been recorded for non-smoking methane-air laminar diffusion flames at pressures from P = 1.5 MPa to P = 6.0 MPa. Soot concentration and temperature profiles were obtained using the spectral soot emission diagnostic method and the Abel inversion deconvolution technique. Visual inspection and measurement of the flame revealed a slight increase in height and decrease in cross-section with increasing pressure. Soot volume fraction increased with pressure according to fv max & prop; P1.4 for 1.5 & le; P & le; 5.0 MPa. The maximum carbon conversion to soot was related to pressure following the relationship eta s, max & prop; P0.55 for 1.5 & le; P & le; 5.0 MPa. The maximum value of carbon converted to soot was etas, max = 10.1% at P = 5.0 MPa. The maximum soot concentration was always found at a height approximately half way between the burner and the flame tip. The temperature was lower in high soot loading regions of the flame. For the same height in the flame, temperature decreased with increasing pressure.

Soot Modeling of a Turbulent Non-premixed Methane/air Flame

Soot Modeling of a Turbulent Non-premixed Methane/air Flame PDF Author: Michael I. B. Chai
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Soot is an important air pollutant. Its formation must be modeled accurately to assist designers in development of low soot emission combustors. This study was concerned with the semi-empirical modeling of soot. The models considered inception, coagulation, agglomeration, and oxidation of the soot particles. Since inception is a key process in the development of soot it was studied in great detail. Two approaches to modeling inception were investigated: acetylene and phenyl. For a methane/air coflow diffusion flame at a pressure of one atmosphere both approaches showed good agreement with experimentally observed trends. Furthermore, the acetylene route under predicted the magnitude of the soot volume fraction while the phenyl route over predicted the magnitude of the soot volume fraction. However, it is believed that the phenyl model will perform better with more complex fuels such as kerosene and with improved laminar flamelet libraries that are optimized for C6 species.

Soot Formation in Propane-air Laminar Diffusion Flames at Elevated Pressures [microform]

Soot Formation in Propane-air Laminar Diffusion Flames at Elevated Pressures [microform] PDF Author: Decio S. (Decio Santos) Bento
Publisher: Library and Archives Canada = Bibliothèque et Archives Canada
ISBN: 9780494024430
Category : Combustion
Languages : en
Pages : 158

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Laminar axisymmetric propane air diffusion flames were studied at pressures 0.1 to 0.725 MPa (1 to 7.25 atm). To investigate the effect of pressure on soot formation, radially resolved soot temperatures and soot volume fractions were deduced from soot radiation emission scans collected at various pressures using spectral soot emission (SSE). Overall flame stability was quite good as judged by the naked eye. Flame heights varied by 15% and flame axial diameters decreased by 30% over the entire pressure range.Analysis of temperature sensitivity to variations in E lambda(m) revealed that a change in E lambda(m) of +/-20% produced a change in local temperature values of about 75 to 100 K or about 5%.Temperatures decreased and soot concentration increased with increased pressure. More specifically, the peak soot volume fraction showed a power law dependence, fv ∝ Pn where n = 2.0 over the entire pressure range. The maximum integrated soot volume fraction also showed a power law relationship with pressure, f ̄v ∝ Pn where n = 3.4 for 1 ≤ P ≤ 2 atm and n = 1.4 for 2 ≤ P ≤ 7.25 atm. The percentage of fuel carbon converted to soot increased with pressure at a rate, etas ∝ Pn where n = 3.3 and n = 1.1 for 1 ≤ P ≤ 2 atm and 2 ≤ P ≤ 7.25 atm respectively.

Soot Measurements in High-Pressure Diffusion Flames of Gaseous and Liquid Fuels

Soot Measurements in High-Pressure Diffusion Flames of Gaseous and Liquid Fuels PDF Author: Gorngrit Intasopa
Publisher:
ISBN: 9780494761816
Category :
Languages : en
Pages : 208

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Book Description
Methane-air, ethane-air, and n-heptane-air over-ventilated co-flow laminar diffusion flames were studied up to pressures of 2.03, 1.52, and 0.51 MPa, respectively, to determine the effect of pressure on flame shape, soot concentration, and temperature. A spectral soot emission optical diagnostic method was used to obtain the spatially resolved soot formation and temperature data. In all cases, soot formation was enhanced by pressure, but the pressure sensitivity decreased as pressure was increased. The maximum fuel carbon conversion to soot, etamax, was approximated by a power law dependence with the pressure exponent of 0.92 between 0.51 and 1.01 MPa, and 0.68 between 1.01 and 2.03 MPa with etamax=9.5% at 2.03 MPa for methane-air flames. For ethane-air flames, the pressure exponent was 1.57 between 0.20 and 0.51 MPa, 1.08 between 0.51 and 1.01 MPa, and 0.58 between 1.01 and 1.52 MPa where etamax=23% at 1.52 MPa. For nitrogen-diluted n-heptane-air flames, etamax=6.5% at 0.51 MPa.

Soot Formation and Its Impact on Flame RadiatioSoot Formation and Its Impact on Flame Radiation During Turbulent Non-Premixed Oxygen-Enriched Combustion of Methane

Soot Formation and Its Impact on Flame RadiatioSoot Formation and Its Impact on Flame Radiation During Turbulent Non-Premixed Oxygen-Enriched Combustion of Methane PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 8

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Soot Formation in Diffusion Flames of Alternative Turbine Fuels at Elevated Pressures

Soot Formation in Diffusion Flames of Alternative Turbine Fuels at Elevated Pressures PDF Author: Arup Barua
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Flow Field and Soot Formation Characteristics in Swirl-stabilized Non-premixed Turbulent Flames

Flow Field and Soot Formation Characteristics in Swirl-stabilized Non-premixed Turbulent Flames PDF Author: Lu-Yin Wang
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Soot formation and evolution in relation with the flow fields were investigated experimentally in turbulent swirl-stabilized non-premixed flames using three different fuels: methane, ethanol and aviation Jet A-1. The studied flames were confined and stabilized in a model gas turbine combustor with a swirl number of ~0.55. Soot volume fraction, fv, and primary soot particle size, dp, were measured using auto-compensating laser-induced incandescence, and planar three-component velocity fields were measured using stereoscopic particle image velocimetry. Measurements of planar laser-induced fluorescence of OH and OH* chemiluminescence were also made for methane and ethanol flames. The OH* field was further Abel-inverted to qualitatively locate the heat release zone. The flow field for all flames featured pronounced inner and outer recirculation zones (IRZ, ORZ), each bounded by their corresponding inner and outer shear layers (ISL, OSL). Abel-inverted OH* intensity maps showed that primary reaction zones occurred in the vicinity of ISL. The central fuel jet penetrating into the IRZ accompanied by a stagnation zone was observed in all methane flames. Soot measurements showed that the overall dp for methane and Jet A-1 flames ranged between 30 nm and 60 nm without discernible trends. In methane flames, peak time-averaged fv occurred between the central jet penetration and the ISL. The decrease and the final disappearance of time-averaged fv were strongly correlated with elevated OH, demonstrating a dominant oxidative attack of OH on soot. With a ~7% increase in air flow rate, the level of soot volume fraction dropped by nearly threefold due to enhanced turbulence intermittency. The appearance of ethanol spray flames, which lacked a bright yellow color, largely differed from others. The absence of soot was confirmed in the laser-induced incandescence measurements. The isothermal flow field of ethanol flames exhibited a large-scale structure of precessing vortex core which was then suppressed under reacting conditions. In Jet A-1 flames, spray pattern changed from V-shaped hollow cone to semi-solid cone when air flow rate increased by 20%, resulting in a 60% reduction in peak time-averaged fv. In contrast to results obtained from the methane flame, soot was found primarily outside the ISL where fuel existed in abundance.