For advanced applications, it is possible to specify directly the interphase mass transfer sources.
If the interphase mass flux 
between any pair of
phases is specified, the volumetric mass source is computed internally
by multiplying by interfacial area density:
 | (5–229) |
Alternatively, you may directly specify the volumetric mass source, or interphase mass flow,
.
In both cases, all transport equations are automatically assigned default secondary sources of the upwinded form:
 | (5–230) |
This default form of secondary sources may be overridden in CCL.