fan

Description

The fan is a general boundary condition to simulate a jump condition between a pair of patches, using the cyclic condition as a base. The condition can accept user-defined fan curve of pressure rise vs velocity.

The non-dimensional flux is calculated as follows:

$$\phi = \frac{120 U_n}{\pi^3 d_m r_{pm}}$$

The non-dimensional pressure:

$$\Psi = \frac{2 \Delta P}{\rho (\pi \omega d_m)^2}$$

Property	Description
$d_m$	Fan mean diameter
$r_{pm}$	Fan rpm
$\Delta P$	Pressure drop
$\omega$	Rotational speed [rad/s]

The non-dimensional table should be given as $\Psi = F(\phi)$.

Usage

The condition requires entries in both the boundary and field files.

Boundary file

<patchName>
{
    type            cyclic;
    ...
}

Field file

<patchName>
{
    // Mandatory entries
    type            fan;
    jumpTable       <Function1<Type>>;

    // Optional entries
    phi             <word>;
    rho             <word>;
    uniformJump     <bool>;
    nonDimensional  <bool>;

    // Conditional entries

      // if 'nonDimensional' is true
      rpm           <Function1<scalar>>;
      dm            <Function1<scalar>>;

    // Inherited entries
    patchType       cyclic;
    ...
}

where:

Property	Description	Type	Required	Default
type	Type name: fan	word	yes	-
jumpTable	Jump dataset	Function1<Type>	yes	-
phi	Name of the flux transporting the field	word	no	phi
rho	Name of the density field for normalising the mass flux	word	no	rho
uniformJump	Flag to apply uniform pressure drop	bool	no	false
nonDimensional	Flag to use non-dimensional curves	bool	no	false
rpm	Fan rpm (for non-dimensional curve)	Function1<scalar>	conditional	-
dm	Fan mean diameter (for non-dimensional curve)	Function1<scalar>	conditional	-

The inherited entries are elaborated in:

• Foam::uniformJumpFvPatchField
• Foam::Function1

• The underlying patchType should be set to cyclic.

Further information

Tutorial:

• TJunctionFan

Source code:

• fan

API:

• Foam::fanFvPatchField

History: Introduced in version 1.5