Sequential Estimation of the Thermal Diffusivity of Three Vegetables Based on an Analysis of 2- and 3-Dimensional Unsteady-state Heat Transfer

Abstract

Thermal diffusivity is an important thermophysical property used in the modeling and computation of unsteady-state heat transfer in basic food processing. The objectives of this study were to propose a new determination method for thermal diffusivity and to examine the applicability of this method to materials of several shapes and sizes. The samples (burdock root, carrot, and radish) were heated in a water bath at 90±1 °C for durations of up to 10 minutes. Then, 2- and 3-dimensional unsteady-state heat conduction problems were solved numerically with a finite element method. The thermal diffusivity of each sample was determined by a sequential estimation method based on the temperature profiles of the sample. The thermal diffusivity values of the samples ranged from (1.1–1.5)×10⁻⁷ m²/s. The thermal diffusivity could be estimated regardless of size, shape, and 2 and 3 dimensions for carrot within the setting range of this experiment.