I have experimentally determined the moisture storage function of several clay bricks in the hygroscopic range up to 96% RH, as well as the effective saturation moisture content at 100% RH.
However, I am missing data for the capillary range between 96% and 100% RH. Would HygroApprox be suitable for estimating this missing part of the moisture storage function? If so, which input parameters would you recommend using for clay bricks?
Thank you for any advice!
Can HygroApprox estimate the capillary range of clay bricks?
Re: Can HygroApprox estimate the capillary range of clay bricks?
Hi Mikaeltm,
the HygroApprox tool is meant to combine data from sorption measurements and mercury porosimetry, but it seems you have no porosimetry data.
What you could to is to fit a "three-point formula" to your data:
https://www.wufi-forum.com/viewtopic.php?t=1980
This formula doesn't really have a physical basis, but it creates a smooth curve which can usually be fit quite well to sorption measurements. At any rate, it produces a much more plausible interpolation curve for a moisture storage function than a simple linear interpolation could do.
You could do such a fit in Excel: Compare the function results with the measured values for the various measured humidities and adjust the two fit parameters until the sum of the squared residuals is a minimum.
The fit process adjusts the position and the steepness of the "step" until it agrees with the measured data. Make sure, however, that the measured data do in fact give some information about the step (i.e. that the data at the highest humidities in the sorption range begin to show some increase or are clearly on the step). If all your data are in the flat region before the step, the positioning and shape of the step would be just guesswork.
And please keep in mind that the result is only an interpolation, not measured data, and that any simulation results which depend critically on any high moisture contents in the interpolated region should be viewed with some suspicion.
Kind regards,
Thomas
the HygroApprox tool is meant to combine data from sorption measurements and mercury porosimetry, but it seems you have no porosimetry data.
What you could to is to fit a "three-point formula" to your data:
https://www.wufi-forum.com/viewtopic.php?t=1980
This formula doesn't really have a physical basis, but it creates a smooth curve which can usually be fit quite well to sorption measurements. At any rate, it produces a much more plausible interpolation curve for a moisture storage function than a simple linear interpolation could do.
You could do such a fit in Excel: Compare the function results with the measured values for the various measured humidities and adjust the two fit parameters until the sum of the squared residuals is a minimum.
The fit process adjusts the position and the steepness of the "step" until it agrees with the measured data. Make sure, however, that the measured data do in fact give some information about the step (i.e. that the data at the highest humidities in the sorption range begin to show some increase or are clearly on the step). If all your data are in the flat region before the step, the positioning and shape of the step would be just guesswork.
And please keep in mind that the result is only an interpolation, not measured data, and that any simulation results which depend critically on any high moisture contents in the interpolated region should be viewed with some suspicion.
Kind regards,
Thomas