Desenvolvimento do método de aquecimento plano parcial para a determinação simultânea de propriedades térmicas sem o uso de transdutores de fluxo de calor

Abstract

This work presents the development of an experimental technique to estimate simultaneously the thermal diffusivity and the thermal conductivity of metallic and non metallic materials. The technique is based on using heating elements and inverse heat conduction procedure. The basic procedure is divided in five different steps: i) an experimental apparatus that allows the imposition of the heat flux in a part of the sample while the remaining surfaces are kept isolated; ii) thermal model deriving; iii) obtaining of a dimensionless heat flux, Q+(t), that is proportional to the heat flux, (t), imposed on the sample, using dynamic observers based on Green s function; iv) thermal diffusivity estimation; v) Estimation of heat flux, (t) and thermal conductivity using the total heat supplied and Q+(t) estimations. The flexibility of the technique proposed includes the measurement of thermal properties metallic and not metallic solid materials from non regular geometry without heat flux transducer. The work also presents the experimental apparatus design as well as the results of the thermal property identification for three different types of materials (stainless steels AISI 304, AISI 410 and Polished Chloride of Vinila (PVC)). A comparison with literature demonstrates the great potentiality of the technique.