## Description🔗

The fanPressure is a pressure boundary condition to assign either a pressure inlet or outlet total pressure condition for a fan. The condition sets the static pressure from a definition of the total pressure and pressure drop as a function of volumetric flow rate across the patch.

The non-dimensional flux is calculated as follows:

$phi = \frac{4 \dot{m}}{\rho \pi^2 d_m^3 \omega}$

The non-dimensional flux is calculated as follows:

$\Psi = \frac{2 \Delta P}{\rho (\pi \omega d_m)}$
Property Description
$$d_m$$ Fan mean diameter [m]
$$\Delta P$$ Pressure drop
$$\omega$$ Rotational speed [rad/s]
$$\dot{m}$$ Mass flow rate

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

The condition sets the static pressure at the patch $$p_p$$ based on a specification of the total pressure, $$p_0$$, and pressure drop, $$p_d$$, specified as a function of the volumetric flow rate.

$p_p = p_0 - p_d$

## Usage🔗

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

### Boundary file🔗

<patchName>
{
type            patch;
...
}


### Field file🔗

<patchName>
{
// Mandatory entries
type            fanPressure;
fanCurve        <Function1<scalar>>;
direction       <word>;

// Optional entries
nonDimensional  <bool>;

// Conditional entries

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

// Inherited entries;
...
}


where:

Property Description Type Required Default
type Type name: fan word yes -
fanCurve Dataset of pressure vs flow rate Function1<scalar> yes -
direction Direction of flow through fan word yes -
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 -

Options for the direction entry:

Property Description
in Into the fan
out Out of the fan

The inherited entries are elaborated in:

## Further information🔗

Tutorial:

Source code:

API:

History:

• Introduced in version 1.5