Solver Settings and Numerical Submodels

The coal particles can be tracked as parcels in an Eulerian-Lagrangian framework. Discrete phase model (DPM) are used to define the injected particles that enter the reactor. In the case of INCI, simulation values for axial velocity of -1.732 m/s and a radial velocity of -l.Om/s of the particles must be provided. If agglomeration is neglected, a maximum particle diameter of 0.1 mm, a mean diameter of 0.09 mm, and a minimum diameter of 0.001 mm are assumed according to a Rosin-Rammler-Sperling-Bennett distribution with a spread parameter of = 0.688 in 10 individual groups for fluid-bed coal (see also Section 3.12.3.3). Particles can be treated as nonspherical with a shape factor of 0.85. 

It is usually sufficient to update the DPM source terms during the calculation after every fiftieth continuous phase iteration. The parcels should be tracked for at most 100 000 steps, applying the discrete random walk model for stochastic tracking with 10 tries at a time scale constant of approximately 0.15. For the 

INCI case, CO was used as a single devolatilizing species. The selected properties of the combusting particle are shown in Table 5.9. 

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Computational Fluid Dynamics Modeling of Coal Gasifiers 147 5.S.2.2 Solver Settings and Numerical Submodels... 

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