Interior Fan
The Interior Fan condition represents interior boundaries where a fan condition is set using a fan pressure curve to avoid an explicit representation of the fan. The Interior Fan defines a boundary condition on a slit for laminar flow. That means that the pressure and the velocity can be discontinuous across this boundary.
One side represents a flow inlet; the other side represents the fan outlet. The fan boundary condition ensures that the mass flow rate is conserved between its inlet and outlet:
This boundary condition acts like a Pressure Conditions boundary condition on each side of the fan. The pressure at the fan outlet is fixed so that the mass flow rate is conserved. On the fan inlet the pressure is set to the pressure at the fan outlet minus the pressure drop induced by the fan. The pressure drop is defined from the static pressure curve, and is usually a function of the flow rate. To define a fan boundary condition on an exterior boundary, the Fan condition should be used instead.
Interior Fan
The Flow direction can be defined by selecting Along normal vector or Opposite to normal vector. This defines which side of the boundary is the fan’s inlet and which side is the fan’s outlet.
Turbulence Conditions on Fan Outlet
When Inlet is selected as the Flow direction and the Turbulence model has transport equations for the turbulent kinetic energy, k, and turbulent dissipation rate, ε, specific dissipation rate, ω, or turbulent relative fluctuations, ζ, the values of the Turbulent kinetic energy, Turbulent relative fluctuations (for the v2-f turbulence model) and the Turbulent dissipation rate or Specific dissipation rate on the downstream side of the fan should be specified. Alternatively, the Reference velocity scale can be used to specify default values
After a boundary has been selected, an arrow displays in the Graphics window to indicate the selected flow direction. If the selection changes, the arrow can be updated by clicking any node in the Model Builder and then clicking the Interior fan node again to update the Graphics window.
The rest of the settings for this section are the same as for the Fan node. See Linear and Static Pressure Curve Data for details.
Location in user interface
Context Menus
Right click the physics interface and select Rotating Machinery>Interior Fan
Ribbon
Physics tab with the physics interface selected:
Boundaries>Rotating Machinery>Interior Fan