Estimation of the temperature-dependent thermal conductivity and specific heat for a cellular concrete

The temperature-dependent thermal conductivity k(T) and specific heat c(p)(T) (or thermal diffusivity) for the cellular concrete of density rho = 643.6 kg.m(3) are simultaneously estimated using an iterative numerical procedure for solution of Coefficient Inverse Heat Conduction Problem (CIHCP) [1]. During the TEMPMEKO'99 Conference the inverse problem was formulated as a one-dimensional and the results of numerical solution vs. DSC Perkin-Elmer Pyris 1 microcalorimeter investigations were shown for plexiglass and polyamide 6 samples [2]. This time, two-dimensional co-ordinate system with axial symmetry is used in order to make more precisely description of the problem. Transient heat flux density and temperature histories at some locations of the sample are necessary for numerical calculations and the data are taken from experimental setup: It consists of four identical specimens; each of 200 mm in diameter and 8 mm of thickness put symmetrically two on each side of a thin electrical heater and of two well insulating plates as the outer parts of,the measurement setup. The temperature histories are measured. experimentally by means of sheathed thermocouples of K-type (NiCr-NiAl) and the data for computational processing are initially smoothed numerically. In the automatic data acquisition system a PC controller with the GPIB interface board is utilised. The temperature interval investigated in the experiment ranges from 300 K to 400 K.