Simultaneous identification of thermophysical and moisture transport properties in porous insulating materials

An inverse technique is applied to the simultaneous reconstruction of thermophysical and mass transfer properties of a porous insulating material subjected to a transient thermal experiment. The identification of the temperature-dependent thermal conductivity and specific heat of the dry material and of the two mass diffusion coefficients related to the moisture content gradient and to the temperature gradient is obtained by the inverse solution of a simplified heat and mass transfer model. The Kalman filter in the LKF (linearised Kalman filter) version is adopted as parameter estimator. The preliminary results, obtained with simulated experiments, show the feasibility of identifying all the unknown parameters, both heat and mass diffusion properties, by the use of thermal measurements only. Moreover, the potential improvement of the estimation process achievable with supplementary information on the moisture content evolution is investigated. The measurement model has been enhanced to handle both the thermal and the moisture response of the specimen, and the quality of the moisture signal has been varied to discover the level of accuracy required to give a significant improvement to the estimation.