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32.3.11 Define/Models/Species/Soot...

The Define/Models/Species/Soot... menu item opens the Soot Model panel.



Soot Model Panel


The Soot Model panel allows you to set parameters related to the soot model. See Section  20.3.3 for details about the items below.

figure

Controls

Soot Formation Model   specifies which model should be used for computing soot formation.

Off   disables the calculation of soot formation.

One-Step   enables the single-step soot model described in Section  20.3.2.

Two-Step   enables the two-step soot model described in Section  20.3.2.

Species Definition   contains inputs for specifying which chemical species in your model should be used as the fuel and oxidizer.

Fuel   is a drop-down list containing all of the defined species. Here you will select the species that is the fuel.

Oxidant   is a drop-down list containing all of the defined species. Here you will select the species that is the oxidizer.

Soot-Radiation Interaction   contains options for modeling the effect of soot on a variable radiation absorption coefficient. This portion of the panel will appear only when one of the radiation models in the Radiation Model panel is active.

None   disables the modeling of soot-radiation interaction.

Generalized Model   enables the soot-radiation interaction model described in Section  13.3.8.

Process Parameters   contains parameters that control the combustion process modeling.

Mean Diameter of Soot Particle   is the assumed average diameter of the soot particles in the combustion system, used to compute the soot particle mass $m_p$ in Equation  20.3-9 for the Two-Step model.

Mean Density of Soot Particle   is the assumed average density of the soot particles in the combustion system, used to compute the soot particle mass $m_p$ in Equation  20.3-9 for the Two-Step model.

Stoichiometry for Soot Combustion   is the mass stoichiometry $\nu_{\rm soot}$ in Equation  20.3-6, which computes the soot combustion rate in both soot models. The default value supplied by FLUENT (2.6667) assumes that the soot is pure carbon and that the oxidizer is O $_2$.

Stoichiometry for Fuel Combustion   is the mass stoichiometry $\nu_{\rm fuel}$ in Equation  20.3-6, which computes the soot combustion rate in both soot models. The default value supplied by FLUENT (3.6363) is for combustion of propane (C $_3$H $_8$) by oxygen (O $_2$).

Model Parameters   contains parameters that control the soot formation model.

Soot Formation Constant   is the parameter $C_s$ in Equation  20.3-3. This item appears only for the One-Step soot model.

Equivalence Ratio Exponent   is the exponent $r$ in Equation  20.3-3. This item appears only for the One-Step soot model.

Equivalence Ratio Minimum   and Equivalence Ratio Maximum are the minimum and maximum values of the fuel equivalence ratio $\phi$ in Equation  20.3-3. Equation  20.3-3 will be solved only if Equivalence Ratio Minimum $< \phi <$ Equivalence Ratio Maximum; if $\phi$ is outside of this range, there is no soot formation. This item appears only for the One-Step soot model.

Activation Temperature of Soot Formation Rate   is the term $E/R$ in Equation 20.3-3. This item appears only for the One-Step soot model.

Magnussen Constant for Soot Combustion   is the constant $A$ used in the rate expressions governing the soot combustion rate (Equations  20.3-5 and 20.3-6). This item appears for both the One-Step and the Two-Step soot models. For the Two-Step model, this input will be called Magnussen Constant for Soot and Nuclei Combustion.

Limiting Nuclei Formation Rate   is the limiting value of the kinetic nuclei formation rate $\eta_0$ in Equation  20.3-12. Below this limiting value, the branching and termination term, ( $f-g$) in Equation  20.3-11, is not included. This item appears only for the Two-Step soot model.

Nuclei Branching-Termination Coefficient   is the term $(f - g)$ in Equation  20.3-11. This item appears only for the Two-Step soot model.

Nuclei Coefficient of Linear Termination on Soot   is the term $g_0$ in Equation  20.3-11. This item appears only for the Two-Step soot model.

Pre-Exponential Constant of Nuclei Formation   is the pre-exponential term $a_0$ in the kinetic nuclei formation term, Equation  20.3-12. This item appears only for the Two-Step soot model.

Activation Temperature of Nuclei Formation Rate   is the term $E/R$ in the kinetic nuclei formation term, Equation  20.3-12. This item appears only for the Two-Step soot model.

Constant Alpha for Soot Formation Rate   is $\alpha$, the constant in the soot formation rate equation, Equation  20.3-9. This item appears only for the Two-Step soot model.

Constant Beta for Soot Formation Rate   is $\beta$, the constant in the soot formation rate equation, Equation  20.3-9. This item appears only for the Two-Step soot model.

Magnussen Constant for Soot and Nuclei Combustion   is the constant $A$ used in the rate expressions governing the soot combustion rate (Equations 20.3-5 and 20.3-6).


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