A two-dimensional mathematical modeling of combustion chambers of coal-fired boilers with a fixed bed

Steady-state combustion has been investigated for both the simulation of reactive turbulent flow within the combustion chamber and a fixed bed of a small-scale coal- red boiler. For this purpose, the one-dimensional code, CLAYER (Biyikoglu 1998), developed for determining the thermo-chemical field of coal combustion in a fixed bed, the zero-dimensional code, CREK (Pratt and Wormek, 1976), used in determining the thermo-chemical field of reactive turbulent flows, and the two-dimensional code, TEACH (Durst and Loy, 1984), used in determining the hydro-dynamical flow field in the combustion chamber, were combined and modified. The unreacted shrinking core model (Ishida and Wen, 1971) was used for coal combustion. The turbulent reactive flow in the combustion chamber is analyzed using k-epsilon turbulence, four-flux radiation, and combustion models, including chemical equilibrium and kinetics calculations. The temperature and gas emission distributions in the fixed bed and combustion chamber are predicted for coal feeding rates 14, 18, and 21 kg/h and for coal types Imported, Soma, and Tuncbilek lignites. The comparison of the existing experimental data with the emission calculations at the exit of the combustion chamber has resulted in an agreement with an acceptable degree.