Modelling the Heat Exchanger Cores as Porous Media

Typically, the small-scale channel structure of a radiator is not resolved by a mesh, but is modelled using porous media. In this tutorial, you use the porous regions approach to specify porosity coefficients for both the air and coolant heat exchanger cores, which yields a certain pressure drop for each stream.

To model the heat exchangers as porous media:
  1. Define the porous region for the air stream.
    1. Select the Regions > Air Core node and set Type to Porous Region.
    2. Expand the Air Core > Physics Values > Porous Inertial Resistance node.
      The Method property is set to Orthotropic Tensor by default. This setting is suitable because the constant resistance coefficients correspond to the principal (diagonal) components of the porous resistance tensor.
    3. Edit the Porous Inertial Resistance > Orthotropic Tensor node and set the properties as follows:
      Node Property Setting
      XX Component Value 1e4 kg/m4
      YY Component Value 1e4 kg/m4
      ZZ Component Value 90 kg/m4
    4. Edit the Porous Viscous Resistance > Orthotropic Tensor node and set the following properties:
      Node Property Setting
      XX Component Value 1e5 kg/m3-s
      YY Component Value 1e5 kg/m3-s
      ZZ Component Value 450 kg/m3-s
  2. Define the porous region for the coolant stream.
    1. Select the Regions > Coolant Core node and set Type to Porous Region.
    2. Edit the Coolant Core > Physics Values > Porous Inertial Resistance > Orthotropic Tensor node and set the following properties:
      Node Property Setting
      XX Component Value 1e8 kg/m4
      YY Component Value 2e6 kg/m4
      ZZ Component Value 1e8 kg/m4
    3. Edit the Porous Viscous Resistance > Orthotropic Tensor node and set the following properties:
      Node Property Setting
      XX Component Value 1e6 kg/m3-s
      YY Component Value 5.5e4 kg/m3-s
      ZZ Component Value 1e6 kg/m3-s
  3. Save the simulation.