Pore and Throat Size Distribution

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Pore and Throat Size Distribution

A major problem with PoreXpert versions before version 2 was that the void size distributions looked unrealistic, and had a discontinuity at maximum size.  This was identified as being due to the existence of void clusters, as explained on the Auto Cluster Ratio page.  You should use the Auto Cluster Ratio facility before outputting pore and throat size distributions, so please read that page and read our publication cited there before continuing. Pore and throat size distributions without the correct cluster ratio are invalid.


The void size distribution graph is as shown below.  A very important feature is that the Total Voids graph asymptotes top right to the sample porosity, thus validating the calculation.




Advanced controls are available in a drop-down menu at the top right-hand side of the graph.  They allow axes to be plotted in logarithmic mode.  This is especially appropriate for the bottom size axis, as voids in porous materials tend to be logarithmically distributed, so within PoreXpert, by default the sizes are histogrammed to 500 intervals logarithmically spaced between the smallest and largest void size within the model, which in turn are set by the highest and lowest experimental intrusion pressure respectively.


Above the left hand graph there is an advanced drop down button which allows the user to change the type of pore and throat size distribution calculated from the unit cell. The options can be used individually or combined in any combination to change the graph displayed by the software.


Normalise data - the normalise data option converts the y-axis on the pore and throat graphs to a percentage value for number or volume, the normalise option makes it easier to compare with results from other experimental techniques.

By volume - the by volume option uses the unit cell structure to determine the volume of all the pores and throats, and converts the y-axis scale to the volume in µm3, or if the normalise data option is chosen the y-axis changes to the percentage volume for each feature size.