Mathematical Modeling of Mass and Heat Transfer of Convective Air Drawing of Apple

Abstract

The aim of the current research is to dry apples using a solar dryer with a desiccant cycle in two modes: direct radiation -convection and indirect radiation -convection. Two types of drying methods, direct and indirect with desiccant and without desiccant, moisture content, and drying in open air were used. Pre - prepared apple slices (flavored with cinnamon) were placed on a specific -sized mesh, the initial weight of the samples was measured, and they were placed inside the solar dryer with a desiccant cycle in two modes: direct radiation -convection and indirect radiation -convection. During the drying process, the evaporation rate, texture, wrinkling, water reabsorption, vitamin C retention, color changes, and sensory characteristics at different treatment levels (30% sucrose and without sucrose, 0.5%, 1%, and 2% cinnamon) were examined. Additionally, several samples were dried as controls without cinnamon flavoring using the solar dryer.

Introduction

Vegetables and fruits are seasonal agricultural products rich in vitamins, minerals, and fiber but have a short shelf life due to high moisture content leading to rapid microbial spoilage. Apples (Malus domestica) are widely grown globally and consumed in various forms, with Afghanistan being a significant producer of multiple high-yield apple varieties.

The study focuses on mathematical modeling of drying apple slices in solar dryers. Moisture ratio (MR) is a key parameter, calculated based on initial, transient, equilibrium, and final moisture content using mass measurements before, during, and after drying. Various thin-layer drying models are tested for accuracy, assessed by statistical parameters: correlation coefficient (R²), chi-square (χ²), and root mean square error (RMSE). The best-fitting model has the highest R² and lowest χ² and RMSE.

The text also lists abbreviations related to the solar drying system and drying process parameters such as temperature, mass flow, drying rate, relative humidity, and power, which are important for modeling and analyzing drying efficiency.

Conclusion

The drying process of the apple slices were experimentally analyzed by means of the industrial solar dryer. During the drying tests, the drying curves of the apple slices were obtained as a function of temperature. The diffusion approximation model was employed to fit the experimental drying curves obtained for constant temperatures. A novel model was proposed based on diffusion approximation model to predict the evaluation of the moisture ratio during the drying process.

References

[1] Jitendra kumar gautam, pankaj verma, IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) e-ISSN: 2278-1684,p-ISSN: 2320-334X, Volume 21, Issue 5 Ser. 1 (Sept. – Oct. 2024), PP 31-37www.iosrjournals.org [2] Jyoti Singh, PankajVerma (2018); Fabricationof HybridSolar Dryer; InternationalJournal ofScientific andResearch Publications, Volume5, Issue (6), (ISSN: 2250-3153). [3] ofM. Villamiel, J. Gamboa, A. C. Soria, E. Riera, J. V. García-Pérez, A. Montilla, Impact of power ultrasound on the quality of fruits and vegetables during dehydration, Physics Procedia. 70 (2015) 828-832. doi.org/10.1016/j.phpro.2015.08.169. [4] A. Kaleta, K. Górnicki, R. Winiczenko, A. Chojnacka, Evaluation of drying models of apple (var. Ligol) dried in a fluidized bed dryer, Energy Conversion and Management. 67 (2013) 179-185. doi.org/10.1016/j.enconman.2012.11.011. [5] V. Palermo, F. Mattivi, R. Silvestri, G. La Regina, C. Falcone, C. Mazzoni, Apple can act as antiaging on yeast cells, Oxidative medicine and cellular longevity, (2012).. doi.org/10.1155/2012/491759. [6] M. kbari, M. Yamaguchi, T. Maejima, S. Otagaki, K. Shiratake S. Matsumoto, Apple cultivation and breeding in Afghanistan: S-RNase genotypes and search system for suitable cultivar combination, International Journal of Agronomy. (2016). doi.org/10.1155/2016/3101864. [7] ANNGO Afghanistan National Nursery Growers Organization Catalogue 2013-2014. (2013).

Copyright

Copyright © 2025 Pushpesh Lal Ranjan, Pankaj Verma. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.