Solid
This node uses this version of the heat equation to model heat transfer in solids:
(6-9)
with the following material properties, fields, and sources:
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ρ (SI unit: kg/m3) is the solid density.
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Cp (SI unit: J/(kg·K)) is the solid heat capacity at constant pressure.
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k (SI unit: W/(m·K)) is the solid thermal conductivity (a scalar or a tensor if the thermal conductivity is anisotropic).
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u (SI unit: m/s) is the velocity field defined by the Translational Motion subnode when parts of the model are moving in the material frame.
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Q (SI unit: W/m3) is the heat source (or sink). Add one or several heat sources as separate physics features. See Heat Source node and Thermoelastic Damping subnode for example.
For a steady-state problem the temperature does not change with time and the first term disappears.
Solid Material
This section is available only when the Local Thermal Non-Equilibrium multiphysics coupling is included in the component to model porous media. It makes it possible to define different material properties for the porous matrix and the fluid.
Select any material from the list to define the Solid material. The default uses the Domain material. See Material Density in Features Defined on the Material Frame for the setting of a temperature-dependent density.
Heat Conduction, Solid
The thermal conductivity k describes the relationship between the heat flux vector q and the temperature gradient ∇T in q = −k∇T, which is Fourier’s law of heat conduction. Enter this quantity as power per length and temperature.
The default Thermal conductivity k is taken From material. For User defined select Isotropic, Diagonal, Symmetric, or Anisotropic based on the characteristics of the thermal conductivity, and enter another value or expression. For Isotropic enter a scalar which will be used to define a diagonal tensor. For the other options, enter values or expressions into the editable fields of the tensor.
The components of the thermal conductivity k when given on tensor form (kxx, kyy, and so on, representing an anisotropic thermal conductivity) are available as ht.kxx, ht.kyy, and so on (using the default name ht). The single scalar mean effective thermal conductivity ht.kmean is the mean value of the diagonal elements kxx, kyy, and kzz.
Fourier’s law assumes that the thermal conductivity tensor is symmetric. A nonsymmetric tensor can lead to unphysical results.
Thermodynamics, Solid
This section sets the thermodynamics properties of the solid.
The heat capacity at constant pressure describes the amount of heat energy required to produce a unit temperature change in a unit mass.
The Density ρ and Heat capacity at constant pressure Cp should be specified.
In addition, the thermal diffusivity α, defined as k ⁄ (ρ Cp) (SI unit: m2/s), is also a predefined quantity. The thermal diffusivity can be interpreted as a measure of thermal inertia (heat propagates slowly where the thermal diffusivity is low, for example). The components of the thermal diffusivity α, when given on tensor form (αxx, αyy, and so on, representing an anisotropic thermal diffusivity) are available as ht.alphaTdxx, ht.alphaTdyy, and so on (using the default physics name ht). The single scalar mean thermal diffusivity ht.alphaTdMean is the mean value of the diagonal elements αxx, αyy, and αzz. The denominator ρ Cp is the effective volumetric heat capacity which is also available as a predefined quantity, ht.C_eff.
Local Thermal Non-Equilibrium
Theory for Heat Transfer in Solids
The Thermoelastic Damping subnode is available from the context menu (right-click the parent node) or from the Physics toolbar, Attributes menu.
When Surface-to-surface radiation is activated, the Opacity subnode is automatically added to the entire selection, with Opaque option selected. The domain selection can’t be edited. To set some part of the domain as transparent, add a new Opacity subnode from the context menu (right-click the parent node) or from the Physics toolbar, Attributes menu.
Heat Generation in a Disc Brake: Application Library path Heat_Transfer_Module/Thermal_Contact_and_Friction/brake_disc
For a detailed overview of the functionality available in each product, visit http://www.comsol.com/products/specifications/
Location in User Interface
Context menus
Heat Transfer>Solid
Heat Transfer in Solids>Solid
Heat Transfer in Fluids>Solid
Heat Transfer in Porous Media>Solid
Heat Transfer in Building Materials>Solid
Bioheat Transfer>Solid
Heat Transfer with Surface-to-Surface Radiation>Solid
Heat Transfer with Radiation in Participating Media>Solid
Ribbon
Physics Tab with interface as Heat Transfer, Heat Transfer in Solids, Heat Transfer in Fluids, Heat Transfer in Porous Media, Heat Transfer in Building Materials, Bioheat Transfer, Heat Transfer with Surface-to-Surface Radiation or Heat Transfer with Radiation in Participating Media selected:
Domains>interface>Solid