![Sample our Built Environment journals, sign in here to start your access, Latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5926/TOC-Subject-Sample-2021-Built-Environment.jpg"})
ABSTRACT
In the present work, the thin layer drying kinetics of potato during natural convection solar drying was investigated experimentally. Cylindrical potato samples with length 50 mm and varying diameter of 8, 10 and 13 mm were dried in an in-house designed and fabricated laboratory scale mixed-mode solar dryer. Thirteen different thin-layer mathematical models were fitted to the experimental moisture ratio (MR) data. The obtained results indicated that the Modified Page model could satisfactorily describe the drying curve of potato cylinders with higher value of R2 and lower values of RMSE and χ2. The shrinkage parameter is incorporated in the analytical diffusion model to study the moisture transfer mechanism of potato cylinders. It was observed that the values of effective diffusion coefficient (Deff) and convective mass transfer coefficient (hm) are overestimated in the range of 85.02–90.27% and 39.11–45.11% for the range of sample diameter examined, without considering the shrinkage effect in the mass transfer analysis. A Multiphysics approach was adopted in this study to get insight into the drying behavior of potato cylinders in terms of food-moisture interactions during the solar drying process. The predicted results of MR are in close agreement with the experimental data. Moreover, the anisotropic behavior of shrinkage as well as the moisture distribution inside the potato cylinder was very well described by Multiphysics model.
Acknowledgement
Special thanks to Miss. Aprajeeta Jha for her valuable help in the simulation study.
Nomenclature
| A | = | surface area, m2 |
| Av | = | area per unit volume, m–1 |
| Bim | = | Biot number for mass transfer |
| C | = | moisture concentration, mol m–3 |
| c0 | = | lag factor |
| D | = | diameter of sample, m |
| Deff | = | effective moisture diffusivity, m2 s–1 |
| hm | = | convective mass transfer coefficient, m s–1 |
| J1 | = | first order Bessel functions of the first kind |
| Jo | = | zeroth order Bessel function of the first kind |
| L | = | length of sample, m |
| M | = | moisture content, kg water.kg dm–1 |
| MR | = | moisture ratio |
| N | = | mass flux, kg m–2 s–1 |
| = | moisture concentration gradient, kg m–3 m–1 | |
| R | = | radius of cylinder, m |
| r | = | radial dimension, m |
| t | = | drying time, s |
| Subscripts | = | |
| 0 | = | at the beginning of drying |
| e | = | at equilibrium |
| f | = | final stage |
| i | = | initial stage |
| s | = | at the surface |
| Symbols | = | |
| ϕ | = | moisture ratio |