Chemical Equilibrium Table Reference

The Chemical Equilibrium model uses a flamelet table called the Chemical Equilibrium Table.

Chemical Equilibrium Table Generator

Properties
None
Right-Click Actions
Import Table…
Loads a previously saved Chemical Equilibrium table.
注Since tables are saved in single precision, Table Precision—under the Chemical Equilibrium Table Generator > Parameters node—is switched to Single after importing a table.
Delete Table
Removes a stored table from memory. The flamelet table must be deleted before making changes to the table settings.
Stop Calculations
Stops the calculations during the flamelet library generation.
Child Nodes
The Chemical Equilibrium Table Generator node contains the following sub-nodes:

Chemistry Definition

The Chemistry Definition describes the species and their thermodynamic properties, from which chemical equilibrium is calculated.
Properties
None
Right-Click Actions
Import Complex Chemistry Definition (Chemkin format)
Activates a standard Open dialog that imports a library file for the complex chemistry definition in Chemkin™ format.
Select Mixture Components
Opens a dialog which allows you to manually select the species from the Material Databases that are available. Use this option if you don't have a Chemkin format mechanism with the species.
Delete Complex Chemistry Definition
Removes the library that is used for the chemistry definition.

Parameters

Properties
Table Precision
Specifies the precision—Single or Double—to which the flamelet table is generated. The default is Single.
Child Nodes
Absolute Pressure
Value
The pressure that is used when generating the flamelet table.
Species for Tabulation
Species
Allows you to select which species are stored in the flamelet table. These species are then made available in a simulation, for example, to use for post-processing in contours or reports.
Emissions
Thermal NOx
When activated, the NOx source term coefficients are calculated and tabulated.
Numerical Settings
Minimum Temperature
Specifies the minimum temperature for enthalpy normalization in the flamelet table.
Numerical Settings > Table Dimensions
Allows you to define the dimensions for the flamelet table. See Table Dimensions Reference.
Heat Loss Ratio Range

Specifies the heat loss ratio range. You can increase the enthalpy space that is covered in the Flamelet table in response to heat loss ratio warnings, or decrease it for better resolution. For example, if your simulation involves heat loss only, with no heat gain, you can set the minimum heat loss ratio limit to 0 and the maximum heat loss ratio to 1.0.

You can set either the minimum heat loss ratio limit or the maximum heat loss ratio limit to 0, but you cannot have both set to 0 at the same time.

Minimum Heat Loss Ratio
Sets the minimum heat loss ratio limit.
Maximum Heat Loss Ratio
Sets the maximum heat loss ratio limit. However, if the resulting minimum temperature drops below a physical limit, the temperature is clipped to the table minimum temperature that is specified at the table generation.

Chemical Equilibrium Table

Properties
Save Table in .sim File
When activated, stores the flamelet table in the sim file. When deactivated, the flamelet table is not stored in the .sim file—which is useful to save disk space when using the same flamelet table in different .sim files, or when auto-saving many sim files. If the flamelet table is required for future use, you must export it manually by right-clicking the flamelet table node and selecting Export Table. Then save it separately from the .sim file.
Path for Table Read
Specifies the file path location of the flamelet table file that has been exported from Simcenter STAR-CCM+ and saved previously. Useful to reduce the .sim file size and save disk space when several .sim files use the same flamelet table.
Verbosity
When activated, if selected tolerance criteria are not met in adaptive grid generation steps, Simcenter STAR-CCM+ prints a summary of tolerance warnings to the Output window at each step during the table generation.
For example:
WARNING: For 'Heat Loss Ratio' the   maximum error of 0.00652988 is greater than the specified tolerance of 0.0001. To achieve the prescribed tolerance, delete the table, increase the maximum number of points (currently 9) and regenerate the table.
When deactivated, all of the warning messages about exceeding the defined tolerance for adaptive table dimensions are hidden.
High Mixture Fraction Limit
For mixture fraction values above a certain limit, the mixture can fail to burn because it is too fuel-rich. Simcenter STAR-CCM+ does not perform the chemical equilibrium calculation above this limit, but calculates a composition for a non-reacting state that is based on pure mixing. To impose this non-reacting state, set this property at less than 1.0.
High Limit Window Size
Allows for a gradual change in flow properties from the reacting to the non-reacting state. Specifically, when you set High Mixture Fraction Limit to a value less than 1.0, the transition from the reacting chemical equilibrium state to the non-reacting pure mixing state can be abrupt as well as discontinuous. The greater the High Limit Window Size (from 0.0 through 1.0), the smoother the transition between the two states.
Right-Click Actions
Generate Chemical Equilibrium and Construct Table
Generates Chemical Equilibrium flamelet libraries and constructs flamelet table.
Print Estimated Maximum Table Size
Prints the estimated maximum table size (in KB) in the output window. This value also appears as a read-only property of the Table Dimensions node.
Export Table
Saves a table that is stored in Simcenter STAR-CCM+’s memory to a file with extension .tbl.
Delete Table
Removes a stored table from memory. The flamelet table must be deleted before making changes to the table settings.
Stop Calculations
Stops the calculations during the flamelet library generation.
Print Table Summary
The Output window displays a summary of the table parameters and conditions with which the table was built. When running the simulation, if the current parameters and conditions differ from those that were specified when the table was built, a warning is displayed in the Output window at each iteration.
Parameters and conditions are not displayed for tables that are imported from Simcenter STAR-CCM+ versions prior to 2406, or from tables that are constructed using DARS libraries.
Child Nodes
Final Table Grid Size
Contains sub-nodes for each of the table dimensions. Each table dimensions sub-node displays the read only, Number of Grid Points, that are used from the data for that parameter. The values are specified before building the table by defining settings under the Table Dimensions node. See Table Dimensions Reference.
Chemical Equilibrium XY Plots
To visualize the chemical equilibrium flamelet table, you can create an XY plot—right-click this node and select New Plot. See Flamelet Table XY Plot Reference.