M. Amendola, H.F. de Campos Velho (2006): Determing Thermal Conductivity for Biological Material in a Drying Process., XV Congress on Numerical Methods and Applications (ENIEF-2006), November 7-10, Santa Fe, Argentine.

Abstract: It is key issue for the Agricultural Engineering to identify thermo physical properties of biological materials. There is a special interest in the thermal conductivity and diffusivity coefficient estimation, which can be performed by comparing data obtained from a specific experimental procedure and theoretical data obtained from some mathematical model – capable for simulating the referred procedure. The experimental data of temperature were previously obtained from one thermal measuring system consisting of concentric cylinders to hold the biological material (a soybean sample in this study), with a heat source placed at the central axis and keeping the cylindrical, as well the circular cross sectional outer surfaces insulated. In such a procedure, only radial heat transfer is effective, minimizing the heat flux in the axial direction. Simulated data of temperature are obtained by using the mathematical model based on the Fourier’s law with initial and boundary conditions according to the experimental procedure, which requires estimative of one the thermal conductivity value. The direct problem is solved by using an implicit forward time and centered space finite difference scheme, with Neumann boundary at the center and the outer surface. Results show a dependency of the thermal conductivity with radial component. The thermal property is estimated by computing the value having the best agreement.