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2. (Optional, pressure-based solver only.) If you are modeling viscous flow and you want to include
the viscous heating terms in the energy equation, enable the Viscous Heating option in the
Viscous Model dialog box.
Models –› Viscous –› Edit...

3. Define thermal boundary conditions at flow inlets, flow outlets, and walls.
At flow inlets and exits you will set the temperature; at walls you may use any of the following
thermal conditions:
w Specified heat flux
w Specified temperature
w Convective heat transfer

w External radiation
w Combined external radiation and external convective heat transfer

4. Materials
Heat capacity and thermal conductivity must be defined, and you can specify many properties as
functions of temperature as described in Chapter 8: Physical Properties.

(c) Modeling Heat Transfer in Two Separated Fluid Regions
If your heat transfer application involves two fluid regions separated by a solid zone or a wall, as
illustrated in Figure 13.2.2, you will need to define the problem with some care. Specifically:
w You should not use outflow boundary conditions in either fluid.
w You can establish separate fluid properties by selecting a different fluid material for each zone.
(For species calculations, however, you can only select a single mixture material for the entire
domain.)

Typical Counter flow Heat Exchanger Involving Heat Transfer between Two Separated Fluid Streams

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