This attached sim file demonstrates the setup and post-processing of Nitrogen Oxide Emissions when using the Flamelet Generated Manifold Model. Only the thermal NOx pathway is activated in this example. See. Modeling NOx Formation with Flamelet Chemistry
. for more information. The sim file is based on the. Example of a Sydney Flame simulated in 2D
The NOx emissions model creates one additional field function for post-processing:Mass Fraction of Nitrogen Oxide Emission
Regulations for NOx emissions often ask NOx to be reported as an emissions Index. An example of how to convert to an emissions index using field functions is given in. How to post-process Nitrogen Oxide Emissions
. These field functions are also included in the attached sim file..
Some important points to note:
1. Since NOx is considered a passive scalar and does not influence the density calculation, the NOx model can be used as a post-processing step in a steady state simulation. Therefore the trigger for the model is set up to begin at 1000 iterations by default. This is set in the properties window of the NOx emissions model in the Physics Continuum. You can change the default for your particular simulation..
2. Calculation of NOx with the Flamelet Generated Manifold model requires the NOx sources to be available in the FGM table. Therefore, you may need to regenerate the FGM table with the Thermal NOx model under Emissions checked if this was left out in the original table generation. This applies to all flamelet based combustion models, although FGM is what is used in this example..
3. You can likely increase the URF for the NOx emissions model to 1.0. Since it is only run after the flow and thermal fields have reached steady state..
The example sim file attached is a demonstration and not an endorsement of a best practice. It is provided to showcase the use of simulation features in a given application. Open the file in a software version equal to or newer than the one specified in the Version Applicable field.
See also:Example of a Sydney Flame simulated in 2D
â€‹Modeling NOx Formation with Flamelet ChemistryHow to post-process Nitrogen Oxide Emissions
STAR-CCM+ Documentation sections:User Guide. >. Modeling Physics. >. Combustion and Other Reacting Flows. >. Flamelet