5.1.1 Definitions
This section explains the terms related to the Common module and their respective definitions:
-
Porosity: Porosity ß is a measure of the void in a (solid) material where fluid can flow through, and is a fraction of the volume of voids over the total volume, with a value between 0 and 1. From continuity or conservation of mass, the fluid velocity through the pores is proportional to the inverse of porosity for the same total flowrate. In Simerics-MP+, the flow velocity inside porous media is the actual flow velocity which is affected by porosity.
-
Mass Fraction Average: For a multicomponent mixture in a selected volume, a mass fraction averaged quantity (
) is computed as: 
5.1
where
The mass fraction of component - 
The variable of component - 
-
Volume Fraction Average: For a multiphase mixture in a selected volume, a volume fraction averaged quantity (
) is computed as: 
5.2
where
The volume fraction of component 
The variable of component 