Determination of thermal diffusivity of persimmon flesh tissue using three-dimensional structure model based on X-ray computed tomography

Computed tomography (CT) images were acquired for an intact fruit and the cell tissues of persimmon flesh using two types of X-ray CT devices. The relationship between the porosity and mean CT value for small tissue samples having a volume of 0.3 mm × 0.3 mm × 0.3 mm was investigated. The three-dimensional microstructure of the issue was reconstructed using image processing software and heat transfer simulation was carried out based on the real structure model. The effective thermal conductivity of the tissue was determined by comparing the results of the three-dimensional (3D) model simulation with those of the homogeneous model simulation and was related to the porosity of the sample. The Brailsford model was selected as the most suitable model to predict the effective thermal conductivity of the tissue. The porosity, thermal conductivity and moisture distributions were visualized for an intact fruit based on analysis of high-resolution X-ray image.