Effects of Aromatics Content and 90% Distillation Temperature of Diesel Fuels on Flame Temperature and Soot Formation

2001 ◽  
Author(s):  
Shinya Takahashi ◽  
Kazunari Wakimoto ◽  
Norimasa Iida ◽  
Danilo Nikolic
Keyword(s):  
Soot Formation ◽  
Flame Temperature ◽  
Diesel Fuels ◽  
Distillation Temperature

scholarly journals Fuel Molecular Structure and Flame Temperature Effects on Soot Formation in Gas Turbine Combustors

1990 ◽  
Vol 112 (1) ◽  
pp. 52-59 ◽  
Author(s):  
O¨. L. Gu¨lder ◽  
B. Glavincˇevski ◽  
M. F. Baksh
Keyword(s):  
Molecular Structure ◽  
Volume Fraction ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Empirical Relationship ◽  
Flame Temperature ◽  
Soot Volume Fraction ◽  
Smoke Point ◽  
Temperature Fields ◽  
Diesel Fuels

A systematic study of soot formation along the centerlines of axisymmetric laminar diffusion flames of a large number of liquid hydrocarbons, hydrocarbon blends, and aviation turbine and diesel fuels was made. Measurements of the attenuation of a laser beam across the flame diameter were used to obtain the soot volume fraction, assuming Rayleigh extinction. Two sets of hydrocarbon blends were designed such that the molecular fuel composition varied considerably but the temperature fields in the flames were kept practically constant. Thus it was possible to separate the effects of molecular structure and the flame temperature on soot formation. It was quantitatively shown that the smoke point height is a lumped measure of fuel molecular constitution. The developed empirical relationship between soot volume fractions and fuel smoke point and hydrogen-to-carbon ratio was applied to five different combustor radiation data, and good agreement was obtained.

scholarly journals Fuel Molecular Structure and Flame Temperature Effects on Soot Formation in Gas Turbine Combustors

1989 ◽  
Author(s):  
Ö. L. Gülder ◽  
B. Glavinčevski ◽  
M. F. Baksh
Keyword(s):  
Molecular Structure ◽  
Volume Fraction ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Empirical Relationship ◽  
Flame Temperature ◽  
Soot Volume Fraction ◽  
Smoke Point ◽  
Temperature Fields ◽  
Diesel Fuels

A systematic study of soot formation along the centerlines of axisymmetric laminar diffusion flames of a large number of liquid hydrocarbons, hydrocarbon blends, and aviation turbine and diesel fuels were made. Measurements of the attenuation of a laser beam across the flame diameter were used to obtain the soot volume fraction, assuming Rayleigh extinction. Two sets of hydrocarbon blends were designed such that the molecular fuel composition varied considerably but the temperature fields in the flames were kept practically constant. Thus it was possible to separate the effects of molecular structure and the flame temperature on soot formation. It was quantitatively shown that the smoke point height is a lumped measure of fuel molecular constitution. The developed empirical relationship between soot volume fractions and fuel smoke point and hydrogen to carbon ratio was applied to five different combustor radiation data, and good agreement was obtained.

PAHs and Soot Emissions in Oxygenated Ethylene Diffusion Flames at Elevated Pressures

2018 ◽  
Author(s):  
Krishna C. Kalvakala ◽  
Suresh K. Aggarwal
Keyword(s):  
Diffusion Flames ◽  
Soot Formation ◽  
Computational Study ◽  
Mixture Fraction ◽  
Flame Temperature ◽  
Primary Objective ◽  
Soot Emission ◽  
Elevated Pressures ◽  
Polycyclic Aromatic ◽  
Soot Emissions

Operating combustion systems at elevated pressures has the advantage of improved thermal efficiency and system compactness. However, it also leads to increased soot emission. We report herein a computational study to characterize the effect of oxygenation on PAHs (Polycyclic Aromatic Hydrocarbons) and soot emissions in ethylene diffusion flames at pressures 1–8atm. Laminar oxygenated flames are established in a counterflow configuration by using N2 diluted fuel stream along with O2 enriched oxidizer stream such that the stoichiometric mixture fraction (ζst) is varied, but the adiabatic flame temperature is not materially changed. Simulations are performed using a validated fuel chemistry model and a detailed soot model. The primary objective of the study was to expand the fundamental understanding of PAH and soot formation in oxygenated flames at elevated pressures. At a given pressure, as the level of oxygenation (ζst) is increased, we observe a significant reduction in PAHs (benzene and pyrene) and consequently in soot formation. Further, at a fixed ζst, as pressure is increased, it leads to increased benzene and pyrene formation, and thus increased soot emission. The reaction path analysis indicates that this can be attributed to the fact that at higher pressures, the C2/C4 path becomes more significant for benzene formation compared to the propargyl recombination path.

scholarly journals Numerical modelling of non-premixed biogas and LPG combustion to study carbon nanostructures formation in flame

2021 ◽  
Author(s):  
Manpreet Kaur ◽  
◽  
Jyoti Bharj ◽  
Rabinder S. Bharj ◽  
Rajan Kumar ◽  
...  
Keyword(s):  
Carbon Nanostructures ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Flame Temperature ◽  
Chemical Species ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Ansys Fluent ◽  
Burner Exit ◽  
Fuel Flow

This work presents the numerical simulation of biogas and LPG fuelled diffusion flames in an axisymmetric chamber to study in-depth, the formation mechanism of soot and carbon nanostructures in these flames. The simulation is formulated on the set of transport equations that involve the equations for conservation of mass (the continuity equation), momentum (Navier-Stokes equation), energy, and chemical species. The governing equations are solved using ANSYS FLUENT, which is centered on the finite volume method. To predict the soot formation, one step soot model has been incorporated. The solution of these equations permits the estimation of temperature field and species concentrations inside the flame. Simulation is conducted at fixed fuel flow rate and varied oxygen flow rates. The results reveal that the formation of soot and carbon nanostructures is strongly dependent on peak flame temperature and concentration of precursor species formed in the flame. Since two fuels produce an exclusive chemical environment in the flame, the flame temperature and CO concentration that is conducive to the growth of carbon nanostructures is higher for LPG fuel as compared to that for biogas. Hence, the nucleation process of carbon nanostructures is faster for LPG than biogas. Moreover, the reactions taking place inside the flame at different locations can also be predicted from flame temperature and species concentration at that location. Pyrolysis of fuel occur near the burner exit, followed by the nucleation and surface growth of carbon nanostructures in the nearby region and oxidation of formed carbon nanostructures near the flame tip.

Phenomenological Analysis of the Combustion of Gaseous Fuels to Measure the Fuel's Energy Quality and Availability to Produce Work in Si Engines, Part 2

2021 ◽  
Author(s):  
Juan Pablo Gomez Montoya ◽  
Andres Amell
Keyword(s):  
Compression Ratio ◽  
Laminar Flame ◽  
Flame Temperature ◽  
Electrical Energy ◽  
Gaseous Fuels ◽  
Diesel Fuels ◽  
Fuel Blends ◽  
Si Engines ◽  
High Turbulence ◽  
Methane Number

Abstract A novel methodology is proposed to evaluate fuel´s performance in spark ignition (SI) engines based on the fuel´s energy quality and availability to produce work. Experiments used a diesel engine with a high compression ratio (CR), modified by SI operation, and using interchangeable pistons. The interchangeable pistons allowed for the generation of varying degrees of turbulence during combustion, ranging from middle to high turbulence. The generating efficiency (ηq), and the maximum electrical energy (EEmax) were measured at the knocking threshold (KT). A cooperative fuel research (CFR) engine operating at the KT was also used to measure the methane number (MN), and critical compression ratio (CCR) for gaseous fuels. Fuels with MNs ranging from 37 to 140 were used: two biogases, methane, propane, and five fuel blends of biogas with methane/propane and hydrogen. Results from both engines are linked at the KT to determine correlations between fuel´s physicochemical properties and the knocking phenomenon. Certain correlations between knocking and fuel properties were experimentally determined: energy density (ED), laminar flame speed (SL), adiabatic flame temperature (Tad), heat capacity ratio (γ), and hydrogen/carbon (H/C) ratio. Based on the results, a mathematical methodology for estimating EEmax and ηq in terms of ED, SL, Tad, γ, H/C, and MN is presented. These equations were derived from the classical maximum thermal efficiency for SI engines given by the Otto cycle efficiency (ηOtto). Fuels with MN > 97 got higher EEmax, and ηq than propane, and diesel fuels.

A Study on Soot Formation and Oxidation of Ethanol / Diesel Blends Using the Two-Color Method

2011 ◽  
Author(s):  
Masanori Wakikawa ◽  
Nobuhide Tachibana ◽  
Zhili Chen ◽  
Mitsuharu Oguma
Keyword(s):  
Oxygen Concentration ◽  
Soot Formation ◽  
Flame Temperature ◽  
Soot Oxidation ◽  
High Oxygen ◽  
High Oxygen Concentration ◽  
Adiabatic Flame Temperature ◽  
Two Factors ◽  
Ethanol Blends ◽  
In The Beginning

In this study, two dimensional distribution of flame temperature and soot concentration was measured with constant volume vessel by the two color method for diesel ethanol blends. As a result, because two factors of decreasing soot formation, which are low adiabatic flame temperature and high oxygen concentration, are synergistic in the beginning of combustion, soot formation is reduced remarkably. In the later stage of the combustion, the flame temperature does not fall, so two enhance effects of soot oxidation, which are early reversal timing and high oxygen concentration, are synergistic. Therefore, in case of diesel ethanol blends, soot formation is reduced by low adiabatic flame temperature and high oxygen concentration, and soot oxidation is enhanced by early reversal timing and high oxygen concentration. Even for an actual engine, soot emission will be decreased because soot formation is reduced and soot oxidation is enhanced.

Experimental study on the combustion characteristics of emulsified diesel in a rapid compression and expansion machine

2000 ◽  
Vol 214 (5) ◽  
pp. 579-586 ◽  
Author(s):  
J. W. Park ◽  
K. Y. Huh ◽  
K. H. Park
Keyword(s):  
High Speed ◽  
Flame Temperature ◽  
Pressure Rise ◽  
Combustion Characteristics ◽  
Test Cases ◽  
Diesel Fuels ◽  
Fuel Droplets ◽  
Pressure Trace ◽  
Compression And Expansion ◽  
Rapid Compression

The combustion characteristics of emulsified diesel fuels are investigated in a rapid compression and expansion machine (RCEM). Among the test cases, the 40 water-oil (W/O) fuel injected at 20° before top dead center (BTDC) has shown the best performance with respect to efficiency and NOx and soot emissions. The pressure trace of the 40 W/O fuel is characterized by a longer ignition delay and a lower rate of pressure rise in premixed combustion. High-speed photographs show reduced flame luminosity and lower flame temperature with increasing W/O ratio. Microexplosions of emulsified fuel droplets, which affect the local shape and brightness of the flame, are identified in magnified flame images.

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