ESTIMATION OF THERMOPHYSICAL PROPERTIES OF A DRYING BODY AT HIGH MASS TRANSFER BIOT NUMBER

摘要

The inverse problem of simultaneously estimating the moisture content and temperature-dependent moisture diffusivity together with the heat and mass transfer coefficients by using only temperature measurements is analysed in this paper. In the convective drying practice, usually the mass transfer Biot number is very high and the heat transfer Biot number is very small. This leads to a very small temperature sensitivity coefficient with respect to the mass transfer coefficient relative to the temperature sensitivity coefficient with respect to the heat transfer coefficient. Under these conditions the relative error of the estimated mass transfer coefficient is high. To overcome this problem, in this paper the mass transfer coefficient is related to the heat transfer coefficient through the analogy between the heat and mass transfer processes in the boundary layer.