The prediction of pulverized Greek lignite combustion in axisymmetric furnaces
- National Technical Univ. of Athens, Dept. of Mechanical Engineering, Fluids Section, Lab. of Aerodynamics, Zografou Campus, 15700 Zografou-Athens (Greece)
A general numerical method for calculating pulverized coal combustion in axisymmetric geometries is utilized, aiming at the optimization of combustion model constants for Greek lignite. The two-equation, k-[epsilon] turbulence model is used for the gas phase, whereas a stochastic approach, based on the lagrangian technique, is used for the particulate phase. The method employs a 'constant devolatilization rate model for both the volatiles and the moisture of the fuel, a char combustion model, a relation of the eddy-dissipation family for the reaction rate of the gaseous mixture, and the nonequilibrium diffusion radiation model. The maximum permissible rate of devolatilization and the preexponential factor of the char oxidation reaction rate are optimized in order to match available experimental data for Greek lignite; these parameters were found to influence considerably, albeit in a different fashion, the combustion process in cylindrical furnaces operating on pulverized lignite. Finally, the liftoff characteristics of the lignite flame were also predicted using a temperature criterion, as well as a flame stability model.
- OSTI ID:
- 6703085
- Journal Information:
- Combustion and Flame; (United States), Journal Name: Combustion and Flame; (United States) Vol. 92:3; ISSN CBFMAO; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
014000* -- Coal
Lignite
& Peat-- Combustion
BROWN COAL
CARBONACEOUS MATERIALS
CHEMICAL REACTIONS
COAL
COMBUSTION
COMMINUTION
DATA
ENERGY SOURCES
EXPERIMENTAL DATA
FLAMES
FORECASTING
FOSSIL FUELS
FUELS
INFORMATION
LIGNITE
MATERIALS
MATHEMATICAL MODELS
NUMERICAL DATA
OXIDATION
THERMOCHEMICAL PROCESSES