On the development of an acoustic permeameter to determining the mean Darcy permeability for porous tissue scaffolds

This paper deals with the permeability determination, with particular attention to the intrinsic Darcian permeability of porous tissue scaffolds, by applying the alternating airflow method (as described in ISO 9053-2), in the peculiar conditions of ultra-slow oscillating flows, in order to keep pure laminar flow condition of Darcy’s regime, with Reynolds number close to unit, (or less). The measurements are performed by using an accurate sub-infrasonic “acoustic permeameter” (i.e., able to generate e quantify infrasound pressure level in the range between 2 Hz and 0.1 Hz), developed and realized at INRIM[I]. The accuracy of the system is established on the basis of a direct microphone calibration procedure, using the permeameter itself as a calibrator, based on the pistonphone principle. Among several applications related to airflow resistivity and permeability, it is of interest the possibility to exploit this system for the measurement of the intrinsic Darcian permeability of porous tissue scaffolds used in regenerative medicine and applied biology. It has been shown that experimental results obtained with this system (in a way according to ISO Standard 9053-2), are compatible with results obtained with the specific Standard ASTM F2952.