Use the Mixture Model (
) multiphysics coupling to simulate heat transfers in fluids containing one or more dispersed phases.
The Phase Transport and the Heat Transfer in Fluids interfaces, which are coupled by the Nonsiothermal Mixture Model multiphysics coupling, solve together for conservation of mass of the dispersed phases and heat transfer in the mixture.
In the Phase Transport interface, it sets the Temperature in the
Model Input section. When the Nonisothermal Mixture Model multiphysics coupling is used together with a
Mixture Model multiphysics coupling that couples the Phase Transport interface with a single-phase flow interface (laminar or turbulent), it also sets the
Temperature in the
Model Input section of the Mixture Model coupling.
The Label is the default multiphysics coupling feature name.
The Name is used primarily as a scope prefix for variables defined by the coupling node. Refer to such variables in expressions using the pattern
<name>.<variable_name>. In order to distinguish between variables belonging to different coupling nodes or physics interfaces, the
name string must be unique. Only letters, numbers, and underscores (_) are permitted in the
Name field. The first character must be a letter.
The default Name (for the first multiphysics coupling feature in the model) is
nitmm1.
When nodes are added from the context menu, you can select Manual (the default) from the
Selection list to choose specific domains to define the mixture model, or select
All domains as needed.
This section defines the physics involved in the multiphysics coupling. The Phase transport and
Heat Transfer lists include all applicable physics interfaces.
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If it is added from the Physics ribbon (Windows users), Physics contextual toolbar (Mac and Linux users), or context menu (all users), then the first physics interface of each type in the component is selected as the default.
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You can also select None from either list to uncouple the node from a physics interface. If the physics interface is removed from the
Model Builder, for example
Phase Transport is deleted, then the
Phase transport list defaults to
None as there is nothing to couple to.
This input appears when a material requires the absolute pressure as a model input. The absolute pressure is used to evaluate material properties, but it also relates to the value of the calculated pressure field. The Absolute Pressure model input is per default computed from the Heat Transfer interface. If the Heat Transfer interface is coupled to a single-phase flow (laminar or turbulent) interface using the
Nonisothermal Flow multiphysics coupling, the absolute pressure will be taken from the single-phase flow interface.
The Absolute pressure field can be edited by clicking
Make All Model Inputs Editable (
) and entering the desired value in the input field.
The default Thermal conductivity kc (SI unit: W/(m·K)) uses values
From material (as selected in the
Materials section for the
Continuous Phase Properties). For
User defined select
Isotropic,
Diagonal,
Symmetric, or
Full based on the characteristics of the thermal conductivity, and enter values or expressions f or the thermal conductivity or its components. For
Isotropic enter a scalar which will be used to define a diagonal tensor. In this case the default is 0 W/(m·K). For the other options, enter values or expressions into the editable fields of the tensor.
Both the heat capacity at constant pressure Cp,c and ratio of specific heats
γc of the continuous phase can be defined.
The default Heat capacity at constant pressure Cp,c (SI unit: J/(kg·K)), uses values
From material. It describes the amount of heat energy required to produce a unit temperature change in a unit mass. For
User defined enter another value or expression. In this case, the default is 0 J/(kg·K).
The default Ratio of specific heat γc (SI unit: 1), uses values
From material. It is the ratio of the heat capacity at constant pressure of the phase,
Cp,c, to the heat capacity at constant volume,
Cv,c. For
User defined enter another value or expression. In this case, the default is 1. For common diatomic gases such as air,
γ = 1.4 is the standard value. Most liquids have
γ = 1.1 while water has
γ = 1.0. γ is used in the streamline stabilization and in the variables for heat fluxes and total energy fluxes.
The number of Dispersed Phase Properties sections depends on the number of phases defined in the coupled Phase Transport interface: the number of sections is equal to the number of dispersed phases, which is in turn equal to the number of phases defined in the coupled Phase Transport interface minus one.
The default Thermal conductivity kd (SI unit: W/(m·K)) uses values
From material (as selected in the
Materials section for the
Dispersed Phase Properties). For
User defined select
Isotropic,
Diagonal,
Symmetric, or
Full based on the characteristics of the thermal conductivity, and enter values or expressions for the thermal conductivity or its components. For
Isotropic enter a scalar which will be used to define a diagonal tensor. In this case the default is 0 W/(m·K). For the other options, enter values or expressions into the editable fields of the tensor.
Both the heat capacity at constant pressure Cp,d and ratio of specific heats
γd of the phase can be defined.
The default Heat capacity at constant pressure Cp,d (SI unit: J/(kg·K)), uses values
From material. It describes the amount of heat energy required to produce a unit temperature change in a unit mass. For
User defined enter another value or expression. In this case, the default is 0 J/(kg·K).
The default Ratio of specific heat γd (SI unit: 1), uses values
From material. It is the ratio of the heat capacity at constant pressure of the phase,
Cp,d, to the heat capacity at constant volume,
Cv,d. For
User defined enter another value or expression. In this case, the default is 1. For common diatomic gases such as air,
γ = 1.4 is the standard value. Most liquids have
γ = 1.1 while water has
γ = 1.0. γ is used in the streamline stabilization and in the variables for heat fluxes and total energy fluxes.