The domain selection inherits all valid domains from its parent feature. For the invalid domains, it shows not applicable.

Select All or one of existing pellets for the non-default Reactions nodes.

A reaction takes usually place in the porous part (fluid) of the pellet, but can also in the whole volume of the pellet. When specifying reaction rate for a bulk species, the specified reaction rate has the basis of the pore volume, or the total volume. With the Pore volume selected, the reaction expression in mol/(m3·s) will be multiplied by pellet’s porosity εpe.

Select a reaction rate (SI unit: mol/(m3·s)) for bulk species i from Rpe, i list. Enter a reaction rate expression when User defined is selected from the list. Alternatively, if reaction rate expressions have been defined in a Chemistry interface (with the Define variables for porous pellets checked under Pellet Chemistry section), they can be chosen from the list.

The section is available when one or more surface species have been added in the Surface Species section of its parent feature (Pellets).

Specify the Reactive specific surface area (total surface reaction area per cubic meter) Sb,reac for all surface reactions.

Under Surface reaction rate for bulk species, specify the rate expression Rspe,i (SI unit: mol/(m2·s)) for the surface reaction rate of each bulk species i participating in the surface reaction. Furthermore, specify the surface reaction rates for the surface species in the Reaction rate for surface species table.

If several pellet types have been defined, one set of surface reaction rates per pellet type can be set by selecting specific pellet under Pellet section. If surface reaction rate expressions have been defined in a Chemistry interface (with the Define variables for porous pellets checked under Pellet Chemistry section), they can be chosen from the list.

Specify the Heat source originating from the heat of chemical reactions inside the pellet. Both heat source Qpe from bulk reactions in the fluid, and heat source Qspe (available when there is one or more surface species) resulting from surface reactions can be defined. With several pellets being added, their heat sources will be summed up.

The heat sources are most conveniently picked up from a Chemistry interface (with the Define variables for porous pellets checked under Pellet Chemistry section) that defines the reaction rate and the heat of reactions. In that case, the heat source expression can be selected from the list. Otherwise you can enter an expression in the text field.