Use the Pellets node to define intraparticle transport and reactions in a packed bed.
Use this section to specify the temperature in the pellets. Select From fluid to use the temperature in the fluid surrounding the pellets. When the pellet temperature is solved for, for example using a
Heat Transfer in Pellets interface, the corresponding temperature is also available.
This section is only available in a Transport of Concentrated Species interface, where the intraparticle flow velocity and pressure is solved for.
When surface reactions are defined in a Chemistry interface, these surface species should be coupled to those defined in the
Pellets node. This is achieved in the
Settings window of said
Chemistry interface. First, select the
Define variables for porous pellets check box in the
Pellet Chemistry section. Then choose the relevant packed bed interface in the
Species solved for list in the
Species Matching section. Finally, type in the dependent variable name in the
Surface species table. The dependent variable is found in the
Shape Functions section in the
Equation View for
Pellets.
When the check box in the Pellet Chemistry section is used, the
Chemistry interface describes the chemistry in the interior of the pellets. To also study the chemistry in the bulk fluid surrounding the pellets in the
Packed Bed, add an additional
Chemistry interface and keep said check box cleared.
When using the Transport of Concentrated Species interface, the molar mass of each surface species is required to convert between molar and mass basis. For a surface species already defined in a
Chemistry interface, say O2(ads), select
Molar mass for O2(ads) for the corresponding surface species (using the column
Molar mass from). Select
User defined to instead enter a constant value or an expression in the column
MolarĀ massĀ (kg/mol).