scholarly journals Experimental Characterization of Flame Structure and Soot Volume Fraction of Premixed Kerosene Jet A-1 and Surrogate Flames

2021 ◽  
Vol 11 (11) ◽  
pp. 4796
Author(s):  
Thomas von Langenthal ◽  
Matthias Martin Sentko ◽  
Sebastian Schulz ◽  
Björn Stelzner ◽  
Dimosthenis Trimis ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Flame Structure ◽  
Soot Volume Fraction ◽  
Aircraft Engine ◽  
Chemical Mechanisms ◽  
Low Emission ◽  
Few Data ◽  
Laser Extinction ◽  
Detailed Chemical

Modeling the chemical reactions and soot processes in kerosene flames is important to support the design of future generations of low-emission aircraft engines. To develop and validate these models, detailed experimental data from model flames with well-defined boundary conditions are needed. Currently, only few data from experiments with real aircraft engine fuels are available. This paper presents measurements of temperature, species and soot volume fraction profiles in premixed, flat flames using Jet A-1 kerosene and a two-component surrogate blend. Measurements were performed using a combination of TDLAS, GC and laser extinction. The results show that the flame structure in terms of temperature and species profiles of the kerosene and surrogate flames are very similar but differ greatly in the resulting soot volume fractions. Furthermore, the study shows that the available chemical mechanisms can correctly predict the temperature profiles of the flames but show significant differences from the experimentally observed species profiles. The differences in the sooting tendency of the kerosene and the surrogate are further investigated using detailed chemical mechanisms.

scholarly journals Effect of the Preheated Oxidizer Temperature on Soot Formation and Flame Structure in Turbulent Methane-Air Diffusion Flames at 1 and 3 atm: A CFD Investigation

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3671
Author(s):  
Subrat Garnayak ◽  
Subhankar Mohapatra ◽  
Sukanta K. Dash ◽  
Bok Jik Lee ◽  
V. Mahendra Reddy
Keyword(s):  
Mole Fraction ◽  
Air Temperature ◽  
Reaction Rate ◽  
Volume Fraction ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Flame Structure ◽  
Soot Volume Fraction ◽  
Computational Domain ◽  
Pressure Elevation

This article presents the results of computations on pilot-based turbulent methane/air co-flow diffusion flames under the influence of the preheated oxidizer temperature ranging from 293 to 723 K at two operating pressures of 1 and 3 atm. The focus is on investigating the soot formation and flame structure under the influence of both the preheated air and combustor pressure. The computations were conducted in a 2D axisymmetric computational domain by solving the Favre averaged governing equation using the finite volume-based CFD code Ansys Fluent 19.2. A steady laminar flamelet model in combination with GRI Mech 3.0 was considered for combustion modeling. A semi-empirical acetylene-based soot model proposed by Brookes and Moss was adopted to predict soot. A careful validation was initially carried out with the measurements by Brookes and Moss at 1 and 3 atm with the temperature of both fuel and air at 290 K before carrying out further simulation using preheated air. The results by the present computation demonstrated that the flame peak temperature increased with air temperature for both 1 and 3 atm, while it reduced with pressure elevation. The OH mole fraction, signifying reaction rate, increased with a rise in the oxidizer temperature at the two operating pressures of 1 and 3 atm. However, a reduced value of OH mole fraction was observed at 3 atm when compared with 1 atm. The soot volume fraction increased with air temperature as well as pressure. The reaction rate by soot surface growth, soot mass-nucleation, and soot-oxidation rate increased with an increase in both air temperature and pressure. Finally, the fuel consumption rate showed a decreasing trend with air temperature and an increasing trend with pressure elevation.

Investigation of Flame Structure and Soot Formation in a Single Sector Model Combustor Using Experiments and Numerical Simulations Based on the LES/CMC Approach

2017 ◽  
Author(s):  
Andrea Giusti ◽  
Epaminondas Mastorakos ◽  
Christoph Hassa ◽  
Johannes Heinze ◽  
Eggert Magens ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Volume Fraction ◽  
Soot Formation ◽  
Flame Structure ◽  
Soot Volume Fraction ◽  
Moment Closure ◽  
Quantitative Prediction ◽  
Lean Burn ◽  
Soot Precursors ◽  
Wide Range

In this work a single sector lean burn model combustor operating in pilot only mode has been investigated using both experiments and computations with the main objective of analyzing the flame structure and soot formation at conditions relevant to aero-engine applications. Numerical simulations were performed using the Large Eddy Simulation (LES) approach and the Conditional Moment Closure (CMC) combustion model with detailed chemistry and a two-equation model for soot. The CMC model is based on the time-resolved solution of the local flame structure and allows to directly take into account the phenomena associated to molecular mixing and turbulent transport which are of great importance for the prediction of emissions. The rig investigated in this work, called Big Optical Single Sector (BOSS) rig, allows to test real scale lean burn injectors. Experiments, performed at elevated pressure and temperature, corresponding to engine conditions at part load, include OH-PLIF and PDA and have been complemented with new LII measurements for soot location. The wide range of measurements available allows a comprehensive analysis of the primary combustion region and can be exploited to further assess and validate the LES/CMC approach to capture the flame behaviour at engine conditions. It is shown that the LES/CMC approach is able to predict the main characteristics of the flame with a good agreement with the experiment in terms of flame shape, spray characteristics and soot location. Finite-rate chemistry effects appear very important in the region very close to the injector exit leading to the lift-off of the flame. Low levels of soot are observed immediately downstream of the injector exit, where a high amount of vaporized fuel is still present. Further downstream, the fuel vapour disappears quite quickly and an extended region characterised by the presence of pyrolysis products and soot precursors is observed. The strong production of soot precursors together with high soot surface growth rates lead to high values of soot volume fraction in locations consistent with the experiment. Soot oxidation is also very important in the downstream region resulting in a decrease of the soot level at the combustor exit. The results show a very promising capability of the LES/CMC approach to capture the main characteristics of the flame, soot formation and location at engine relevant conditions. More advanced soot models will be considered in future work in order to improve the quantitative prediction of the soot level.

Effects of morphology and wavelength on the measurement accuracy of soot volume fraction by laser extinction

2017 ◽  
Vol 29 (1) ◽  
pp. 015202 ◽  
Author(s):  
Ya-fei Wang ◽  
Qun-xing Huang ◽  
Fei Wang ◽  
Yong Chi ◽  
Jian-hua Yan
Keyword(s):  
Measurement Accuracy ◽  
Volume Fraction ◽  
Soot Volume Fraction ◽  
Laser Extinction

Measurement of soot distribution in two cross-sections in a gasoline direct injection engine using laser-induced incandescence with the laser extinction method

2017 ◽  
Vol 233 (2) ◽  
pp. 211-223 ◽  
Author(s):  
Xiao Ma ◽  
Yue Ma ◽  
Liang Zheng ◽  
Yanfei Li ◽  
Zhi Wang ◽  
...  
Keyword(s):  
Cross Sections ◽  
Volume Fraction ◽  
Direct Injection ◽  
Soot Volume Fraction ◽  
Gasoline Direct Injection ◽  
Visible Range ◽  
Direct Injection Engine ◽  
Gasoline Direct Injection Engine ◽  
Laser Induced Incandescence ◽  
Laser Extinction

An approach based on regression was developed to reveal the soot volume fraction (SVF) distribution of a horizontal cross-section in an optically accessible gasoline direct injection engine, based on the quantitative data in vertical images from planar laser-induced incandescence, which was calibrated by the laser extinction method (LEM). The approach used the matching of the corresponding pixels in the vertical and the horizontal images to solve the problem of visible range that limited the use of the LEM in measuring SVFs of the horizontal plane. Local SVFs of as low as 0.05 ppm can be detected. Analysis of both the horizontal and vertical image results showed that the case of ϕa = 0.7 (equivalent air–fuel ratio) resulted in significantly rich soot regions with a peak SVF approximately three times higher than that of the case with ϕa = 0.8.

OH PLIF and Soot Volume Fraction Imaging in the Reaction Zone of a Liquid-Fueled Model Gas-Turbine Combustor

2004 ◽  
Author(s):  
Terrence R. Meyer ◽  
Sukesh Roy ◽  
Sivaram P. Gogineni ◽  
Vincent M. Belovich ◽  
Edwin Corporan ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Reaction Zone ◽  
Large Scale ◽  
Volume Fraction ◽  
Soot Formation ◽  
Flame Structure ◽  
Soot Volume Fraction ◽  
Gas Turbine Combustor ◽  
Planar Laser ◽  
Model Gas Turbine Combustor

Simultaneous measurements of OH planar laser-induced fluorescence (PLIF) and laser-induced incandescence (LII) are used to characterize the flame structure and soot formation process in the reaction zone of a swirl-stabilized, JP-8-fueled model gas-turbine combustor. Studies are performed at atmospheric pressure with heated inlet air and primary-zone equivalence ratios from 0.55 to 1.3. At low equivalence ratios (φ < 0.9), large-scale structures entrain rich pockets of fuel and air deep into the flame layer; at higher equivalence ratios, these pockets grow in size and prominence, escape the OH-oxidation zone, and serve as sites for soot inception. Data are used to visualize soot development as well as to qualitatively track changes in overall soot volume fraction as a function of fuel-air ratio and fuel composition. The utility of the OH-PLIF and LII measurement system for test rig diagnostics is further demonstrated for the study of soot-mitigating additives.

scholarly journals Investigation of Soot Formation in a Novel Diesel Fuel Burner

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1993 ◽  
Author(s):  
Natascia Palazzo ◽  
Matthias Kögl ◽  
Philipp Bauer ◽  
Manu Naduvil Mannazhi ◽  
Lars Zigan ◽  
...  
Keyword(s):  
Diesel Fuel ◽  
Volume Fraction ◽  
Soot Formation ◽  
Soot Volume Fraction ◽  
Morphological Characterization ◽  
Diesel Combustion ◽  
Elastic Light Scattering ◽  
Laser Induced Incandescence ◽  
Fuel Burner

In the present work, a novel burner capable of complete pre-vaporization and stationary combustion of diesel fuel in a laminar diffusion flame has been developed to investigate the effect of the chemical composition of diesel fuel on soot formation. For the characterization of soot formation during diesel combustion we performed a comprehensive morphological characterization of the soot and determined its concentration by coupling elastic light scattering (ELS) and laser-induced incandescence (LII) measurements. With ELS, radii of gyration of aggregates were measured within a point-wise measurement volume, LII was employed in an imaging approach for a 2D-analysis of the soot volume fraction. We carried out LII and ELS measurements at different positions in the flame for two different fuel types, revealing the effects of small modifications of the fuel composition on soot emission during diesel combustion.

scholarly journals Soot volume fraction fields in unsteady axis-symmetric flames by continuous laser extinction technique

2012 ◽  
Vol 20 (27) ◽  
pp. 28742 ◽  
Author(s):  
Muhammad Kashif ◽  
Jérôme Bonnety ◽  
Philippe Guibert ◽  
Céline Morin ◽  
Guillaume Legros
Keyword(s):  
Volume Fraction ◽  
Soot Volume Fraction ◽  
Continuous Laser ◽  
Laser Extinction
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