The components and reactions that are postprocessed are one-way coupled to the main simulation. This means that there is no effect on mixture properties or heat release. The list of components and reactions for postprocessing are specified by the user.
Postprocessing components:
No contribution to mixture properties (density, static enthalpy)
No contribution to total mass
Postprocessing reactions:
Generate sources for components that are also postprocessed
Generate no source for regular components (that is, not postprocessed ones)
No heat release
The above model assumptions are justified if the component mass
fractions and reaction turnover are small relative to the bulk mixture.
A typical application is the simulation of pollutants; for example,
NO formation. The transport equations for postprocessing components
are solved at the end of the flow analysis after the solving of the
main equations. When the postprocessing reactions require a temperature
variance equation (reaction rate option is Arrhenius with
Temperature PDF) and the variance equation was not solved
during the analysis, then temperature variance will be postprocessed
as well. In this case, the temperature variance equation will be solved
first to convergence or maximum number of iterations and is then followed
by the postprocessing components group.
Note: For steady-state cases, chemistry postprocessing is not performed at the end of the flow analysis if the termination of the flow analysis was due to a user-defined solver interrupt condition. For details, see Interrupt Control in the CFX-Pre User's Guide.