Large-eddy Simulation of Pilot-assisted Pulverized-coal Combustion in a Weakly Turbulent Jet
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Large-eddy simulation has been performed to investigate pilot-assisted pulverized-coal combustion in a weakly turbulent air jet. An advanced pyrolysis model, the chemical percolation devolatilization (CPD) model, has been incorporated into the LES framework to predict the local, instantaneous pyrolysis kinetics of coal particles during the simulation. Prediction on volatile species generation is thus improved, which provides an important initial condition for gas-phase volatile and solid-phase char combustion. For gas-phase combustion, the partially stirred reactor (PaSR) model is employed to model the combustion of volatile species, taking into account subgrid turbulence-chemistry interactions. For heterogeneous solid-phase char combustion, both the intrinsic chemical reaction on the internal surface of a char particle and the diffusion of gaseous oxidant through the film layer around the particle have been incorporated by using a kinetic/diffusion surface reaction model. The LES results show overall good agreements with experimental data. Sensitivity analysis has been performed to better understand the impact of parameter uncertainties on the LES results.
KeywordsLarge-eddy simulation Chemical percolation devolatilization Pulverized-coal combustion Partially stirred reactor
This work was performed by the first author KDW when he was a Research Assistant at Brunel University London under the support of the Engineering and Physical Sciences Research Council (EPSRC) of the UK and the China Scholarship Council. The research was also supported by the National Natural Science Foundation of China (51422605, 51390491) and National Basic Research Program of China (2012CB214906). This work used the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk).
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Conflict of interests
The authors declare that they have no conflict of interest.
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