spheres_and_cylinders

openpnm.models.geometry.diffusive_size_factors.spheres_and_cylinders(target, pore_diameter='pore.diameter', throat_diameter='throat.diameter')[source]

Computes diffusive shape coefficient for conduits assuming pores are spheres and throats are cylinders.

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.

  • pore_diameter (str) – Name of the dictionary key on target where the array containing pore diameter values is stored

  • throat_diameter (str) – Name of the dictionary key on target where the array containing pore diameter values is stored

Returns

size_factors – A dictionary containing the diffusive size factors, which can be accessed via the dict keys ‘pore1’, ‘pore2’, and ‘throat’.

Return type

dict

Notes

The diffusive size factor is the geometrical part of the pre-factor in Fick’s law:

\[n_A = \frac{A}{L} \Delta C_A = S_{diffusive} D_{AB} \Delta C_A\]

Thus \(S_{diffusive}\) represents the combined effect of the area and length of the conduit, which consists of a throat and 1/2 of the pore on each end.