Modeling and simulation of moisture transfer during solar drying of carrot slices

Abstract

Carrot slices of 0.03 m diameter and 0.005 m thickness were dried in direct, indirect and mixed mode type natural convection solar dryers. Thin layer drying behavior of carrot slices was studied using 10 empirical and semi‐empirical mathematical models. Wang and Singh model described the drying behavior of carrot accurately with maximum values of coefficient of determination (R2) and minimum reduced chi‐square (χ2), and root mean square error (RMSE). The effective diffusivity (Deff) and convective mass transfer coefficient (hm) of carrot slices ranged from 2.59 × 10−8−6.36 × 10−8 m2/s and 3.15 × 10−7 to 4.28 × 10−7 m/s, respectively, with maximum values obtained for mixed mode solar dried samples followed by direct and indirect solar dried samples. The diffusivity of carrot slices dried in direct, indirect and mixed‐mode solar dryer were expressed as a function of temperature using Arrhenius relation. Finite element model was developed using COMSOL Multiphysics software to simulate moisture ratio during drying. The developed model predicted the transient moisture migration phenomenon inside the samples precisely during the drying process.