The eddy dissipation concept (EDC)
model with the consideration of the intermediate reactions for the
volatile matter (VM) combustion was applied to simulate turbulent
pulverized coal/air jet combustion adjacent to a bluff-boy type model
burner. The VM of the coal was assumed to consist of CO, H2, and CH4, and its chemistry was described by a 16-speices
and 41-step skeletal mechanism for CH4/air combustion.
The model was compared with some other conventionally used ones, including
the eddy dissipation (ED) model, eddy dissipation or finite rate (ED-FR)
model, mixture fraction probability density function (MF-PDF) model,
and the EDC model with a global reaction mechanism for gas phase combustion
(EDC_G), in predicting temperature profiles, maximum flame temperature,
flame shape, and ignition position and in CPU cost. The predicted
temperature profiles and flame positions were further compared with
reported experimental data. It was found that the EDC model with the
consideration of the intermediate reactions for VM combustion improved
prediction in the temperature field and thus ignition position. With
the adoption of the full in situ adaptive tabulation (ISAT) method,
two-third of the overall CPU time could be saved, making the EDC model
more acceptable in comparison with the ED-type models and MF-PDF model.
On the basis of the simulation results, it is suggested that intermediate
reactions of the VM should be considered when high accuracy of flame
temperature and ignition position prediction is desired in simulation
of pulverized coal combustion.