33.4.1 Create/Edit Materials Dialog Box

The Create/Edit Materials dialog box is used to create and modify materials. Materials can be downloaded from the global database or defined locally. See Chapter  8 for details about defining material properties. Section  8.1.2 describes how to use the dialog box.

Controls

Name   shows the name of the material. If you edit this field, the new name will take effect when you click on Change/Create.

Chemical Formula   displays the chemical formula for the material. You should generally not edit this field unless you are creating a material from scratch.

Material Type   is a drop-down list containing all of the available material types. By default, fluid and solid will be the only choices. If you are modeling species transport/combustion, mixture will also be available. For problems in which you have defined discrete-phase injections, inert-particle, droplet-particle, and/or combusting-particle will also appear.

FLUENT Fluid Materials   allows you to choose the fluid material for which you want to modify properties. This option is available when fluid is selected in the Material Type drop-down list.

FLUENT Solid Materials   allows you to choose the solid material for which you want to modify properties. This option is available when solid is selected in the Material Type drop-down list.

FLUENT Mixture Materials   allows you to choose the mixture material for which you want to modify properties. This option is available when mixture is selected in the Material Type drop-down list.

FLUENT Droplet Particle Materials   allows you to choose the droplet-particle for which you want to modify properties. This option is available when droplet-particle is selected in the Material Type drop-down list.

Order Materials by   allows you to order the materials in the Materials list alphabetically by Name or alphabetically by Chemical Formula.

FLUENT Database...   opens the FLUENT Database Materials dialog box, from where you can copy materials from the global database into the current solver.

User-Defined Database...   opens the Open Database dialog box, where you can specify the user-defined database to be used.

Properties   contains input fields for the material properties that are required for the active physical models.

Density   sets the material density. You may set a constant value, or select one of the other methods from the drop-down list above the real number field. See Section  8.3 for instructions on setting density.

Cp   sets the constant-pressure specific heat of the material. You may set a constant value, or select one of the other methods from the drop-down list above the real number field. See Section  8.7 for instructions on setting specific heat.

Thermal Conductivity   sets the thermal conductivity of the material. You may set a constant value, or select one of the other methods from the drop-down list above the real number field. See Section  8.5 for instructions on setting thermal conductivity.

Viscosity   sets the viscosity of the material. You may set a constant value, or select one of the other methods from the drop-down list above the real number field. See Section  8.4 for instructions on setting viscosity.

Molecular Weight   sets the molecular weight of the material. It is used to derive the gas constant of the material.

Standard State Enthalpy   specifies the formation enthalpy of a fluid material for a reacting flow. See Section  8.10 for details.

Standard State Entropy   specifies the standard state entropy of a fluid material for a reacting flow. This input is used only if the fluid material is involved in a reversible reaction. See Section  8.11 for details.

Reference Temperature   specifies the reference temperature for the Heat of Formation.

L-J Characteristic Length   specifies the kinetic theory parameter $\sigma$ for a fluid material. See Section  8.13 for details.

L-J Energy Parameter   specifies the kinetic theory parameter $\epsilon/k$ for a fluid material. See Section  8.13 for details.

Absorption Coefficient   specifies the absorption coefficient $a$ for radiation heat transfer. See Section  8.8 for details. If you choose the wsggm-user-specified option from the drop-down list next to Absorption Coefficient, the WSGGM User Specified dialog box will open.

Scattering Coefficient   specifies the scattering coefficient $\sigma_s$ for radiation heat transfer (only for the P-1, Rosseland, or DO radiation model). See Section  8.8 for details.

Scattering Phase Function   specifies an isotropic (by default) or linear-anisotropic scattering function. If you are using the DO model, delta-eddington and user-defined scattering functions are also available. See Section  8.8 for details. If you choose delta-eddington, the Delta-Eddington Scattering Function dialog box will open.

Refractive Index   specifies the refractive index for the material. It is used only when semi-transparent media are modeled with the DO radiation model.

Mixture Species   specifies the names of the species that comprise a mixture material. To check or modify these names, click on the Edit... button to open the Species dialog box. This property appears only for mixture materials.

Reaction   displays the reaction mechanism being used when you are modeling finite-rate reactions. finite-rate appears if Laminar Finite-Rate or Eddy-Dissipation Concept is selected in the Species Model dialog box, eddy-dissipation appears if Eddy-Dissipation is selected, and finite-rate/eddy-dissipation appears if Finite-Rate/Eddy-Dissipation is selected.

Click Edit... to open the Reactions dialog box.

Mechanism   allows you to enable different reactions selectively in different geometrical zones. Click the Edit button to open the Reaction Mechanisms dialog box. See Section  15.1.3 for details.

Mass Diffusivity   contains a drop-down list of available methods for specifying the diffusion coefficients for the species in a mixture material. If you select constant-dilute-appx, you will enter a constant value in the field below. If you select dilute-approx or multicomponent, the Mass Diffusion Coefficients dialog box will open, and you can specify the coefficients there. If you select kinetic-theory, you will need to specify the kinetic theory parameters for the individual fluid materials (species) that comprise the mixture. See Section  8.9 for details about specifying mass diffusivity.

Thermal Diffusion Coefficient   contains a drop-down list of available methods for specifying the thermal diffusion coefficients for the species in a mixture material. If you select kinetic-theory, you will need to specify the kinetic theory parameters for the individual fluid materials (species) that comprise the mixture. If you select specified, the Thermal Diffusion Coefficients dialog box will open, and you can specify the coefficients there. See Section  8.9.4 for details about specifying thermal diffusion coefficients.

Density of Unburnt Reactants   sets the density ( $\rho_u$ in this equation in the separate Theory Guide) of the unburnt products.

Temperature of Unburnt Reactants   sets the temperature ( $T_u$ in this equation in the separate Theory Guide) of the unburnt products.

Adiabatic Temperature of Burnt Products   (only for adiabatic premixed combustion models) specifies the value of the burnt products under adiabatic conditions, $T_{\rm ad}$ in this equation in the separate Theory Guide.

Molecular Heat Transfer Coefficient   specifies the molecular heat transfer coefficient ( $\alpha$ in this equation in the separate Theory Guide) for use with the premixed combustion model. See Chapter  17 for details.

Laminar Flame Speed   specifies the value of $U_l$ in this equation in the separate Theory Guide.

Critical Rate of Strain   specifies the value of $g_{\rm cr}$ in this equation in the separate Theory Guide.

Heat of Combustion   (only for non-adiabatic premixed combustion models) specifies the value of $H_{\rm comb}$ in this equation in the separate Theory Guide.

Unburnt Fuel Mass Fraction   (only for non-adiabatic premixed combustion models) specifies the value of $Ystar{\rm fuel}$ in this equation in the separate Theory Guide.

Thermal Expansion Coefficient   specifies the thermal expansion coefficient ( $\beta$ in Equation  13.2-2) for use with the Boussinesq approximation.
See Section  13.2.4 for details.

Droplet Surface Tension   specifies the value of the droplet surface tension ( $\sigma$ in this equation in the separate Theory Guide).

Latent Heat   is the latent heat of vaporization, $h_{\rm fg}$, required for phase change from an evaporating liquid droplet or for the evolution of volatiles from a combusting particle. See Section  23.5 for details.

Thermophoretic Coefficient   specifies the thermophoretic coefficient ( $D_{T,p}$ in this equation in the separate Theory Guide), and appears when the thermophoretic force is included in the discrete phase calculation.

Vaporization Temperature   is the temperature, $T_{\rm vap}$, at which the calculation of vaporization from a liquid droplet or devolatilization from a combusting particle is initiated by ANSYS FLUENT. See Section  23.5 for details.

Boiling Point   is the temperature, $T_{\rm bp}$, at which the calculation of the boiling rate equation is initiated by ANSYS FLUENT. See Section  23.5 for details.

Vapor-Particle-Equilibrium   is the selected approach for the calculation of the vapor concentration of the components at the surface. This can be Raoult's law ( this equation in the separate Theory Guide), the Peng-Robinson real gas model ( this equation in the separate Theory Guide), or a user-defined function that provides this value.

Volatile Component Fraction   ( $f_{v0}$) is the fraction of a droplet particle that may vaporize via Laws 2 and/or 3 ( this section in the separate Theory Guide). For combusting particles, it is the fraction of volatiles that may be evolved via Law 4 ( this section in the separate Theory Guide). See Section  23.5 for details.

Binary Diffusivity   is the mass diffusion coefficient, $D_{i,m}$, used in the vaporization law, Law 2. This input is also used to define the mass diffusion of the oxidizing species to the surface of a combusting particle, $D_{i,m}$. See Section  23.5 for details.

Saturation Vapor Pressure   is the saturated vapor pressure, $P_{\rm sat}$, defined as a function of temperature, which is used in the vaporization law, Law 2. See Section  23.5 for details.

Heat of Pyrolysis   is the heat of the instantaneous pyrolysis reaction, $h_{\rm pyrol}$, that the evaporating/boiling species may undergo when released to the continuous phase. The heat of pyrolysis should be input as a positive number for exothermic reaction and as a negative number for endothermic reaction. The default value of zero implies that the heat of pyrolysis is not considered. See Section  23.5 for details.

Degrees of Freedom   specifies the kinetic theory parameter $f$, which is the number of nodes of energy storage. This parameter is required only if you are defining specific heat via kinetic theory. See Section  8.13 for details.

Particle Emissivity   is the emissivity of particles in your model, $\epsilon_p$, used to compute radiation heat transfer to the particles when the P-1 or DO radiation model is active and particle radiation interaction is enabled in the Discrete Phase Model dialog box. See Section  23.5 for details.

Particle Scattering Factor   is the scattering factor, $f$, due to particles in the P-1 or DO radiation model. Note that this property will appear only if particle radiation interaction is enabled in the Discrete Phase Model dialog box. See Section  23.5 for details.

Particle Scattering Factor   

Swelling Coefficient   is the coefficient, $C_{\rm sw}$, which governs the swelling of the coal particle during the devolatilization law, Law 4. A swelling coefficient of unity (the default) implies that the coal particle stays at constant diameter during the devolatilization process. See Section  23.5 for details.

Burnout Stoichiometric Ratio   is the stoichiometric requirement, $S_b$, for the burnout reaction, in terms of mass of oxidant per mass of char in the particle. See Section  23.5 for details.

Combustible Fraction   is the mass fraction of char, $f_{\rm comb}$, in the coal particle, i.e., the fraction of the initial combusting particle that will react in the surface reaction, Law 5. See Section  23.5 for details.

React. Heat Fraction Absorbed by Solid   is the parameter $f_h$, which controls the distribution of the heat of reaction between the particle and the continuous phase. The default value of zero implies that the entire heat of reaction is released to the continuous phase. See Section  23.5 for details.

Heat of Reaction for Burnout   is the heat released by the surface char combustion reaction, Law 5. This parameter is input in terms of heat release (e.g., Joules) per unit mass of char consumed in the surface reaction. See Section  23.5 for details.

Devolatilization Model   defines which version of the devolatilization model, Law 4, is being used. If you want to use the default constant rate devolatilization model, retain the selection of constant in the drop-down list to the right of Devolatilization Model and input the rate constant $A_0$ in the field below the list.

Choose single-rate, two-competing-rates, or cpd-model in the drop-down list to activate one of the optional devolatilization models (the single kinetic rate model, two kinetic rates model, or CPD model, as described in this section in the separate Theory Guide).

When the single kinetic rate model ( single-rate) is selected, the Single Rate Devolatilization dialog box will appear; when the two competing rates model ( two-competing-rates) is selected, the Two Competing Rates Model dialog box will appear; and when the CPD model ( cpd-model) is selected, the CPD Model dialog box will appear.

See Section  23.5 for details.

Combustion Model   defines which version of the surface char combustion law (Law 5) is being used. If you want to use the default diffusion-limited rate model, retain the selection of diffusion-limited in the drop-down list. No additional inputs are necessary, because the binary diffusivity defined above will be used in this equation in the separate Theory Guide.

To use the kinetics/diffusion-limited rate model for the surface combustion model, select kinetics/diffusion-limited in the drop-down list and enter the parameters in the resulting Kinetics/Diffusion-Limited Combustion Model dialog box.

To use the intrinsic model for the surface combustion model, select intrinsic-model in the drop-down list and enter the parameters in the resulting Intrinsic Combustion Model dialog box.

To use the multiple surface reactions model, select multiple-surface-reactions in the drop-down list.

See Section  23.5 for details.

Pure Solvent Melting Heat   specifies the latent heat for the melting and solidification model ( $L$ in this equation in the separate Theory Guide).

Solidus Temperature   specifies the solidus temperature for the melting and solidification model ( $T_{\rm solidus}$ in this equation in the separate Theory Guide).

Liquidus Temperature   specifies the liquidus temperature for the melting and solidification model ( $T_{\rm liquidus}$ in this equation in the separate Theory Guide).

Pure Solvent Melting Temperature   specifies the melting temperature of pure solvent ( $T_{\rm melt}$ in this equation and this equation in the separate Theory Guide) for the melting and solidification model when species transport has also been enabled. The solvent is the last species material of the mixture material.

Eutectic Temperature   is the lowest alloy melting temperature, which depends on the relative proportions of the mixture composition of the Eutectic specie mass fractions.

Slope of Liquidus Line   specifies the slope of the liquidus surface with respect to the concentration of the solute fluid ( $m_i$ in this equation and this equation in the separate Theory Guide). It is not necessary to specify this value for the solvent. Note that this option is available only for the melting and solidification model when species transport has also been enabled.

Partition Coefficient   specifies the partition coefficient with respect to the concentration of the solute fluid ( $K_i$ in this equation and this equation in the separate Theory Guide). It is not necessary to specify this value for the solvent. Note that this option is available only for the melting and solidification model when species transport has also been enabled.

Diffusion in Solid   specifies the rate of diffusion in the solid. Note that this option is available only for the melting and solidification model when species transport has also been enabled.

UDS Diffusivity   specifies the diffusion coefficient for a user-defined scalar. This material property is available in the Create/Edit Materials dialog box when you specify one or more user-defined scalars in the User Defined Scalars dialog box.If you select defined-per-uds, you will need to specify the diffusion coefficient for each user-defined scalar transport equation in the UDS Diffusion Coefficients dialog box.

When you are viewing the database, additional properties may be displayed. However, after you copy the material to the local area, only the properties with relevance to the current problem will be displayed.

Change/Create   changes the properties of a locally-stored material or creates a new one in the local area. If no material with the specified Name exists locally, ANSYS FLUENT will create it. If you have modified the material without changing its name, ANSYS FLUENT will simply update the material with your modifications. If you have assigned a new name to the material and a material with this name already exists locally, an error will be indicated; you must then specify a different name or delete the existing material with that name before trying to save the new material.

Delete   deletes the currently selected material from the local materials list. It has no effect on the global database.