SIMULTANEOUS ESTIMATIONS OF TEMPERATURE-DEPENDENT THERMAL-CONDUCTIVITY AND HEAT-CAPACITY

A hybrid numerical algorithm of the Laplace transform technique and th e control-volume method is proposed to simultaneously estimate the tem perature-dependent thermal conductivity and heat capacity from tempera ture measurements inside the material. But, the functional forms of th e thermal conductivity and heat capacity are unknown a priori. The who le domain is divided into several sub-layers and then the thermal prop erties in each sub-layer are assumed to be linear functional forms of temperature before performing the inverse calculation. The accuracy an d efficiency of the predicted results can be evidenced from various il lustrated cases using simulated exact and inexact temperature measurem ents obtained within the medium. Results show that good estimations on the thermal properties can be obtained from the knowledge of the tran sient temperature recordings only at two selected locations. The advan tage of the present method is that the relation between the thermal pr operties and temperature can be determined for various types of bounda ry conditions even though the early temperature data cannot be obtaine d. (C) 1998 Elsevier Science Ltd. All rights reserved.