Determination of Darcian permeability of porous material by infrared spectrometry

Abstract The active cooling of aerospace structures can be performed by the use of porous materials. It requires characterizing its permeability to predict the cooling effi-ciency by means of Computational Fluid Dynamics codes. The Darcian term is generally deduced experimentally from a relationship between the mass flow rate and the pressure drop through the porous media. Due to thermo-chemical process involved in the cooling, the permeability can change. It is currently not possible with common techniques to determine these variations during the flight. This paper presents a novel approach taking advantage of well known flow behaviour in chemical reactor engineering in order to propose a real-time in situ quantification of the Darcian permeability. The residence time distribution is analyzed thanks to tracer injection and to associate