D O M A I N S E L E C T I O N

Select the domains where you want to add an out-of-plane heat flux.

U P S I D E I N W A R D H E A T F L U X

Select between specifying the upside inward heat flux directly or as a convective term using a heat transfer coefficient.

•Click the General inward heat flux button to specify a value or expression for the

inward (or outward, if the quantity is negative) heat flux through the upside (SI unit: W/m2) in the q0,u field.

•Click the Inward heat flux button to specify an inward (or outward, if the quantity is

negative) heat flux through the upside (SI unit: W/m2) as hu·(Text,u T). Enter a

value or expression for the heat transfer coefficient in the hu field

(SI unit: W/(m2·K) and a value or expression for the external temperature in the Text,u field (SI unit: K). The default value for the external temperature is 293.15 K.

D O W N S I D E I N W A R D H E A T F L U X

The controls in the Downside Inward Heat Flux section are identical to those in the Upside Inward Heat Flux section except that they apply to the downside instead of the

upside.

Change Thickness

Select the Out-of-plane heat transfer check box on the Heat Transfer

interface to add this feature to 2D models.

2D

The Change Thickness feature makes it possible model domains with another thickness than the overall thickness that is specified in the Heat Transfer feature’s Physical Model section.

D O M A I N S E L E C T I O N

Select the domains where you want to use a different thickness.

C H A N G E T H I C K N E S S

Specify a value for the Thickness dz (SI unit: m). The default value is 1 m. This value replaces the overall thickness in the domains that are selected in the Domain Selection section.

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T h e H e a t T r a n s f e r i n P o r o u s M e d i a I n t e r f a c e

After selecting Heat Transfer in Porous Media, found under the Heat Transfer branch () in the Model Wizard, a Heat Transfer () node is added to the Model Builder with these default nodes: Porous Matrix, Heat Transfer in Fluids, Thermal

Insulation, and Initial Values. Right-click the main node to open a context menu and add as many nodes as required to define the equations, properties and boundary conditions.

The Heat Transfer in Porous Media interface () is an extension of a the generic Heat Transfer interface that includes modeling heat transfer through convection, conduction and radiation, conjugate heat transfer, and non-isothermal flow. The ability to define material properties, boundary conditions and more for porous media heat transfer is activated by selecting the Heat transfer in porous media check box on the Heat Transfer Settings window (Figure 13-1).

Figure 13-1: The ability to model porous media heat transfer is activated by selecting the Heat transfer in porous media check box in the Heat Transfer Settings window.

All of the sections and settings in Figure 13-1, and many of the heat transfer features, are described in The Heat Transfer Interfaces in the

COMSOL Multiphysics User’s Guide. Only sections unique to the Heat

Note Transfer in Porous Media interface, and to the module being used, are described in this section.

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