ransohoff_snap_off

openpnm.models.physics.capillary_pressure.ransohoff_snap_off(target, shape_factor=2.0, wavelength=5e-06, require_pair=False, surface_tension='pore.surface_tension', contact_angle='pore.contact_angle', diameter='throat.diameter', vertices='throat.offset_vertices', **kwargs)[source]

Computes the capillary snap-off pressure assuming the throat is cylindrical with converging-diverging change in diamater - like the Purcell model. The wavelength of the change in diamater is the fiber radius.

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.

  • shape_factor (float) – A constant dependent on the shape of throat cross-section 1.75 - 2.0, see Ref [1]

  • wavelength (float or array like) – The transverse interfacial radius of curvature at the neck (fiber radius in fibrous media)

  • require_pair (bool) – Controls whether snap-off requires a pair of arc meniscii to occur.

  • 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

References

[1]: Ransohoff, T.C., Gauglitz, P.A. and Radke, C.J., 1987. Snap‐off of gas bubbles in smoothly constricted noncircular capillaries. AIChE Journal, 33(5), pp.753-765.