The
Define/Models/Species/NOx... menu item opens the
NOx Model panel.
NOx Model Panel
The
NOx Model panel allows you to set parameters related to the NOx postprocessor. See Section
20.1.10 for details about the items below.
Controls
Formation
tab contains the parameters to define NOxmodel.
Pathways
contains toggle buttons for activating the NOx models to be used for the calculation of NO and HCN concentrations.
Thermal NO
enables calculation of thermal NOx.
Prompt NO
enables the calculation of prompt NOx.
Fuel NO
enables the calculation of fuel NOx.
N2O Intermediate
enables the formation of NOx through
N2O Intermediate. This option will appear only if one of the NO model is active.
User-Defined Functions
contains controls for selecting a
NOx Rate UDF. See the separate UDF Manual for details.
Replace with UDF Rate
replaces any or all of
FLUENT's NOx rate calculations with your own user-defined NOx rate
Reduction
tab contains the reduction parameters.
Methods
contains list of reduction methods.
Reduction Method Parameters
(This item will not appear until one of the other
Models is turned on.)
Reburn
enables the calculation of NO reburning effects.
SNCR
enables the calculation of NOxreduction by SNCR method.
Turbulence Interaction
contains parameters related to the effect of turbulent fluctuations on the NOx formation. See Section
20.1.9 for details.
PDF Mode
is a drop-down list containing options that take into account turbulent fluctuations when you compute the specified NO formation. See Section
20.1.10 for details.
temperature
includes fluctuations of temperature.
temperature/species
fluctuations of temperature and mass fraction of the species selected in the
Species drop-down list (which appears when you select this option).
Mixure Fraction
includes fluctuation in the mixture fraction(s). This is available for non-premixed combustion calculations only.
Beta PDF Points
controls the number of points at which the beta function in Equation
20.1-104 or Equation
20.1-105 will be integrated. The default value of 10, which indicates that the beta function will be integrated at 10 points on a histogram basis, will yield an accurate solution with reasonable computation time. Increasing this value may improve accuracy, but will also increase the computation time. (This item will appear only if you have selected one of the four PDF modes for turbulence interaction.)
Formation Model Parameters
contains the parameters associated with the selected
NOxmodel.
Thermal
contains parameters for modeling thermal NO. (This section will appear only if Thermal NO is enabled under Models.)
[O]Model
is a drop-down list in which you can select the method to be used for calculation of thermal NOx. To choose the equilibrium method, select
equilibrium. To choose the partial equilibrium method, select
partial-equilibrium. To choose the predicted O concentration method, select
instantaneous. See Section
20.1.3,
20.1.3, and
20.1.3 for details.
[OH]Model
is a drop-down list in which you can select the method to be used for calculation of thermal NOx. To exclude OH, select
none. To choose the partial equilibrium method, select
partial-equilibrium. To choose the predicted OH concentration method, select
instantaneous. See Sections
20.1.3,
20.1.3, and
20.1.3 for details.
Replace with UDF Rate
replaces any or all of
FLUENT's NOx rate calculations with your own user-defined NOx rate.
Prompt
contains parameters for modeling prompt NO. (This section will appear only if
Prompt NO is enabled under
Models.)
Fuel Species
is a list containing all of the defined species. You will select the species that is the fuel.
Fuel Carbon Number
specifies the number of carbon atoms per fuel molecule.
Equivalence Ratio
is the ratio of the actual fuel/air ratio to the stoichiometric fuel/air ratio.
Fuel
contains parameters for modeling fuel NO. (This section will appear only if
Fuel NO is enabled under
Models.)
Fuel Type
specifies the type of fuel NOx to be calculated.
Solid
enables the calculation of solid fuel NOx.
Liquid
enables the calculation of liquid fuel NOx.
Gas
enables the calculation of gas fuel NOx.
N Intermediate
allows you to specify any one of the
HCN,
NH3, or
HCN/NH3/NO as the intermediate species. See Section
20.1.5 for details.
Volatile N Mass Fraction
specifies the mass fraction of nitrogen in the volatiles. This parameter appears only for
Solid fuel NOx calculations.
Conversion Fraction
specifies the overall fraction of fuel N (for gas and liquid) or volatile N (for solid), by mass, that will be converted to immediate species and/or product NO. This option will appear only if you have selected
HCN/NH3/NO as the intermediate species.
Partition Fractions
specifies the fraction of the converted fuel N (for gas and liquid) or volatile N (for solid), by mass, that will become HCN and NH3. This option will appear only if you have selected
HCN/NH3/NO as the intermediate species.
Char N Conversion
is a drop-down list in which you can select
NO,
HCN, or
NH3 as the species to which the char N is converted (when you are calculating solid fuel NOx). This parameter appears only for
Solid fuel NOx calculations. See Section
20.1.10 for details.
Char N Mass Fraction
specifies the mass fraction of nitrogen in the char. This parameter appears only for
Solid fuel NOx calculations.
BET Surface Area
sets the BET internal pore surface area (see
Section
20.1.5 for details) of the particles. This parameter appears only for
Solid fuel NOx calculations.
Fuel N Mass Fraction
specifies the mass fraction of nitrogen in the fuel (kg nitrogen per kg fuel). This parameter appears only for
Gas or
Liquid fuel NOx calculations.
N2O Path
contains the method to be used for formation of NO through an
O intermediate. (This section will appear only if
N2O Intermediate is enabled under
Models.)
N2O Model
contains the drop-down list of available N2O models.
quasi-steady
enables the quasi-steady-state method of calculation (The transport equation for the species
O will not be solved).
transported-simple
enables the transported simple method of calculation (The pollutant species
O is added in the species list and it's mass fraction will be calculated using the transport equations).
[
Reduction Method Parameters] contains the methods of reduction.
Reburn
tab activates the NOxreduction by reburn method.
Reburn Model
contains the drop-down list of reburn methods.
instantaneous[CH]
activates instantaneous method in the
Reburn Model. When you choose this method a warning to include CH,
, and
will be displayed.
partial-equilibrium
activates partial method in the
Reburn Model.
Reburn Fuel Species
contains reburn fuel species drop-down list.
Equivalent Fuel Type
contains equivalent fuel type drop-down list.
SNCR
contains the drop-down list of SNCR methods
Injection Method
contains the parameters for NOxreduction by SNCR method.
Gaseous Injection
includes ammonia as a gas phase pollutant species from the injection locations.
Liquid Injection
includes liquid phase pollutant species from the injection locations.
Reagent Species
contains the list of the liquid phase pollutants available. This option is available only if the
Liquid Injection is selected as
Injection Method.