The engineering of unit cells allows simulations of the effect of changes of void network characteristics, such as void sizes, connectivity and porosity. Such changes may be induced by the effects process such as the weathering of porous building stone (followed by a permeability or wetting simulation), the compression of a sintered filter (followed by a filtration efficiency simulation), or the reduction of available mobile fluid void space due to a static fluid (followed by a permeability calculation to calculate relative permeability).
If you Run new operation... immediately on starting the PoreXpert software, then a manual Unit Cell Building page will open. This allows you to enter manual unit cells with varying parameters. Such an approach is appropriate if you wish to alter, for example, porosity, connectivity or correlation level of the network, but is not advised for altering sizes, as the effects of, for example, altering the throat skew and spread parameters operate via the background Euler beta distribution parameters.
If you wish to change either the actual or effective void sizes, then the best approach is to create a unit cell from the percolation products of your baseline material, and then alter the sizes of selected voids using the Targeted Modification facility.
The Engineering option can also be used for matching the properties of a unit cell to void networks where the geometry is known, but not the percolation characteristics - for example the results of X-ray CT scans (CAT scans) or reconstructions from synchrotron radiation facilities such as the Diamond Light Source. However, the matching has to be by trial and error, as PoreXpert currently does not have any algorithm for convergence onto the geometric characteristics of networks.