washburn¶
- openpnm.models.physics.capillary_pressure.washburn(target, surface_tension='pore.surface_tension', contact_angle='pore.contact_angle', diameter='throat.diameter')[source]¶
Computes the capillary entry pressure assuming the throat in a cylindrical tube.
- Parameters
target (OpenPNM Base object) – Object with which this model is associated. This controls the length of the calculated array, and also provides access to other necessary properties.
surface_tension (str) – Name of the dictionary key on
target
pointing to the array containing values of surface tension. If a pore property is given, it is interpolated to a throat list.contact_angle (str) – Name of the dictionary key on
target
pointing to the array containing values of contact angle. If a pore property is given, it is interpolated to a throat list.diameter (str) – Name of the dictionary key on
target
pointing to the array containing values of throat diameter
- Returns
values – A numpy ndarray containing the computed values of capillary entry pressure
- Return type
ndarray
Notes
The Washburn equation is:
\[P_c = -\frac{2\sigma(cos(\theta))}{r}\]This is the most basic approach to calculating entry pressure and is suitable for highly non-wetting invading phases in most materials.