Shrinking Core Reactions
Use this node to define core consuming reaction rate for solid species (part of the unreacted core) and surface reaction rate for bulk species.
The core consuming reaction is a kind of surface reaction which takes place on the unreacted core surface. The core is shrinking when the solid species is being consumed in the surface reaction.
Domain Selection
The node inherits all valid domains from its parent feature. For the invalid domains, not applicable is shown.
Pellet
Select All or one of existing pellets for the Shrinking Core Reactions node.
core consuming reactions
If there is one solid species only, the core shrinking rate depends on the consumed rate of this species. If there are more than one solid species, the core shrinking rate depends on the weighted mass consumed rate of all species, assuming that the same consumed rate is held for all species along core axial direction.
In the Core species reaction rate table, select the reaction rate (SI unit: mol/(m2·s)) for solid species under column Surface reaction rate. The reaction rate could be coupled to Chemistry with the Define variables for porous pellets (under Pellet Chemistry section) being checked. With User defined being selected from column Surface reaction rate, enter a reaction rate expression under the column Surface rate expression (mol/(m^2*s)).
For the bulk species which take part in the core consuming reactions or other surface reactions on the core surface, the reaction rate is some kind of molar flux between core surface and reacted layer.
Select bulk species reaction rate (or molar flux, SI unit: mol/(m2·s)) for bulk species i from Jpe, i list. The reaction rate could be picked up from Chemistry with Define variables for porous pellets being checked. Enter a reaction rate expression when User defined is selected from the list.
Heat Source
Specify the Heat source originating from the heat (QsRc) of surface reactions on the core surface. 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 selected under Pellet Chemistry section) that defines the heat of surface reactions. In that case, the heat source expression can be selected from the list. Otherwise you can enter an expression in the text field.
The heat source (on extra dimension) can be picked by Heat Source feature under the Pellets feature of heat transfer interface. The total heat source (including heat from Porous Layer Reactions nodes, on base domain) can be used by a Heat Source feature in any of the heat transfer interfaces.