The Char Burnout Kinetics (CBK) model describes char oxidation under conditions relevant to pulverized coal combustion processes. It includes effects of thermal annealing and ash inhibition on the char combustion. The form of this model that is available in Ansys Fluent only applies to atmospheric conditions and has no statistical kinetics.

The CBK model can be defined as a material property in the Create/Edit Materials dialog box (Figure 12.1: The Create/Edit Materials Dialog Box with the CBK Model Selected) for problems in which you have defined discrete-phase injections.

 Physics → Materials → Create/Edit...

Figure 12.1: The Create/Edit Materials Dialog Box with the CBK Model Selected

Once you have selected combusting-particle from the Material Type drop-down list, you can select cbk from the Combustion Model drop-down list in the Properties group box. The New CBK-8 Combustion Model dialog will open, allowing you to set the char reactivity parameters (see Figure 12.2: The New CBK-8 Combustion Model Dialog Box). The default values are acceptable.

Figure 12.2: The New CBK-8 Combustion Model Dialog Box