Modelling of heat and moisture transport during drying black grapes

P>In this work, heat and moisture transport occurred during drying of black grapes in a laboratory dryer were investigated. In the experiments, the air was passed through the chamber at a variety of flow rates (0.5, 0.75, 1.0 and 1.25 m s-1) and temperatures (40, 50, 60 and 70 degrees C). Thermal and moisture diffusivities were determined. The possibility of expressing the moisture removal from the grapes was searched with the fourteen one-layer drying models selected from the literature. Among all the models, the Page model was found the best for explaining the experimental results. The effects of the drying temperature and air velocity on the constants and coefficients of Page model and diffusivities were also investigated by multiple combinations of the different equations as the linear, power, logarithmic, exponential, polynomial, inverse polynomial and Arrhenius type by non- linear regression analyses. Models obtained were also analysed statistically using t-test, RMSE, MBE and chi 2.