Assessing the Role of Particles in Radiative Heat Transfer during Oxy-Combustion of Coal and Biomass Blends

Table 2

Summary of physical models employed in the CFD simulations.

Physical models	Primary modeling option	Other modeling options explored in the sensitivity analysis
Coal devolatilization	The two competing rates (Kobayashi) model
Biomass devolatilization	The two competing rates (Kobayashi) model	Constant devolatilization rate (20 sec^−1)
Gas-phase chemistry	Two steps: (1) char oxidation to CO, (2) CO oxidation to CO2
Gas-phase radiative property	Perry (5 gg) [11]^*
Turbulence	Realizable k-ε
Radiative transport equation solver	Discrete ordinates method (angular resolution, theta × phi: 3 × 3)
Particle radiative property	Variable and (Table 1)^*	Constant and (corresponding to that of char in cf. Table 2);
Particle scattering phase function	Anisotropic (forward scattering)	Isotropic scattering
Fuel particle size distribution (PSD) at inlet	Rosin-Rammler distributions (Figure 1); (8 diameter intervals)	Rosin-Rammler distributions (Figure 1); (40 diameter intervals)
Particle swelling coefficient; (during devolatilization)	1 (no change in particle diameter; during devolatilization)	1.5 (particle diameter increases by 50% during devolatilization)

These models were implemented as User-Defined Functions (UDFs) in ANSYS FLUENT.