- openpnm.models.physics.capillary_pressure.purcell(target, r_toroid, surface_tension='pore.surface_tension', contact_angle='pore.contact_angle', diameter='throat.diameter')¶
Computes the throat capillary entry pressure assuming the throat is a toroid.
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.
r_toroid (float or array_like) – The radius of the toroid surrounding the pore
surface_tension (str) – Name of the dictionary key on
targetpointing 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
targetpointing 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
targetpointing to the array containing values of throat diameter
values – A numpy ndarray containing the computed values of capillary entry pressure
- Return type
This approach accounts for the converging-diverging nature of many throat types. Advancing the meniscus beyond the apex of the toroid requires an increase in capillary pressure beyond that for a cylindical tube of the same radius. The details of this equation are described by Mason and Morrow , and explored by Gostick  in the context of a pore network model.
G. Mason, N. R. Morrow, Effect of contact angle on capillary displacement curvatures in pore throats formed by spheres. J. Colloid Interface Sci. 168, 130 (1994).
J. Gostick, Random pore network modeling of fibrous PEMFC gas diffusion media using Voronoi and Delaunay tessellations. J. Electrochem. Soc. 160, F731 (2013).