Estimation of thermophysical properties of moist materials under different drying conditions

Abstract

This article deals with the solution for the inverse problem of simultaneously estimating moisture content and temperature-dependent moisture diffusivity, together with thermal conductivity, heat capacity, density, and phase conversion factor of a drying body as well as boundary condition coefficients, by using only temperature measurements. Two different physical problems, convective and contact drying, are examined and compared. The present parameter estimation problem is solved with the Levenberg-Marquardt method of minimization of the least-squares norm, by using simulated experimental data. The temperature responses during the drying are obtained with a numerical solution of the non-linear one-dimensional Luikov's equations. As a representative drying body, a mixture of bentonite and quartz sand with known thermophysical properties has been chosen. Analyses of the sensitivity coefficients and of the determinant of the information matrix are presented. © 2005 Taylor & Francis Group Ltd.