Temperature During Convective Drying of Thin Flat Wet Materials
https://doi.org/10.21122/1029-7448-2024-67-6-516-529
Abstract
. The basic laws of the kinetics of drying thin flat materials during the period of drop in the drying speed are outlined. A method for calculating the average integral temperature of wet material on the basis of the relative temperature coefficient of drying is presented. Experimental data are processed based on the relative drying rate in the drying processes of ceramics, asbestos, and woolen fabric. A formula for calculating the average temperature is proposed. The solution of the differential equation of thermal conductivity for a wet plate during the drying process (namely during the period of drop in the drying speed) under boundary conditions taking into account the conditions of drying is given. The calculation of the heat transfer coefficient is given, too. Based on the study of various sources and processing of experimental results, formulas for calculating the thermal conductivity coefficient of wet materials have been presented. The analytical solution of the problem confirmed that during convective drying in low-intensity processes of the second drying period, the temperature change with a decrease in moisture content turns from an exponential dependence smoothly into a linear one, which is completely consistent with the experiment. A comparison of the temperature calculation by the experimental formula with the results of analytical solutions has been presented. A sufficiently reliable coincidence of experimental and calculated analytical values of temperature for the period of drop in speed drying of ceramics, asbestos, and fabric is obtained.
About the Authors
A. I. Ol’shanskii
Vitebsk State Technological University
Belarus
Belarus
Address for correspondence:
Ol’shanskii Anatolii I. –
Vitebsk State Technological University,
72, Moskovsky Ave.,
220035, Vitebsk, Republic of Belarus.
Tel.: +375 29 112-79-25
tm@vstu.by
A. A. Kotow
Vitebsk State Technological University
Belarus
Belarus
Vitebsk
S. M. Kuzmenkov
Vitebsk State Technological University
Belarus
Belarus
Vitebsk
References
1. Lykov A. V. (1968) Drying Theory. Moscow, Energiya Publ. 472 (in Russian).
2. Krasnikov V. V. (1973) Conductive Drying. Moscow, Energiya Publ. 288 (in Russian).
3. Akulich P. V. (2010) Calculations of Drying and Heat Exchange Installations. Minsk, Belaruskaya Navuka Publ. 443 (in Russian).
4. Rudobashta S. P. (1980) Mass-and-Heat Transfer in Solid-Phase Systems. Moscow, Khimiya Publ. 248 (in Russian).
5. Lykov A. V., Kuts P. S., Ol'shanskii A. I. (1972) Kinetics of Heat Transfer during the Desiccation of Moist Materials. Journal of Engineering Physics and Thermophysics, 23, 1082–1086. https://doi.org/10.1007/BF00832214.
6. Vasilyev V. N., Kutsakova V. E., Frolov S. V. (2013) Drying Technology. Basics of Heat and Mass Transfer. Saint-Petersburg, Giord Publ. 224 (in Russian).
7. Ol’shanskii A. I. (2013) Heat Transfer Kinetics and Experimental Methods for Calculating the Material Temperature in the Drying Process. Journal of Engineering Physics and Thermophysics, 86, 622–633. https://doi.org/10.1007/s10891-013-0876-1.
8. Kuts P. S., Ol’shanskii A. I. (1975) Approximate Method of Calculating the Kinetics of Convective Drying of Flat Materials. Journal of Engineering Physics, 28 (4), 419–422. https:// doi.org/10.1007/bf00878212.
9. Ol’shanskii A. I., Golubev A. N. (2023) Investigation of the Kinetics of Heat and Moisture Exchange during Heat Treatment and Drying of Thin Wet Thermal Insulation Materials. Enеrgеtika. Izvestiya Vysshikh Uchebnykh Zavedenii i Energeticheskikh Ob’edinenii SNG = Energetika. Proceedings of CIS Higher Education Institutions and Power Engineering Associations, 66 (1), 66–79. https://doi.org/10.21122/1029-7448-2023-66-1-66-79 (in Russian).
10. Lykov A. V. (1961) Theoretical Foundations of Construction Thermophysics. Minsk, AN BSSR Publ. 519 (in Russian).
11. Lykov A. V. (1946) Theory of Drying Capillary-Porous Colloidal Materials of the Food Industry. Moscow, Pishchepromizdat Publ. 286 (in Russian).
12. Lykov A. V. (1967) Theory of Thermal Conductivity. Moscow, Vysshaya Shkola Publ. 600 (in Russian).
13. Zhuravleva V. P. (1972) Mass Transfer in the Course of Heat Treatment and Drying of Capillary-Porous Building Materials. Minsk, Nauka i tekhnika Publ. 192 (in Russian).
14. Ol’shanskii A. I., Zhernosek S. V., Gusarov A. M. (2018) Calculation of the Kinetics of Heat Transfer Using the Experimental Data of Moisture Exchange in the Process of Convective Drying of Thin Flat Materiаls. Vestsi Natsyyanal’nai Akademii Navuk Belarusi. Seryya Fizika-Technichnych Navuk = Proceedings of the National Academy of Sciences of Belarus. PhysicalTechnical Series, 63 (3), 333–341. https://doi.org/10.29235/1561-8358-2018-63-3-333-341 (in Russian).
15. Ol’shanskii A. I., Gusarov A. M. (2020) Temperature of Material in the Process of Convective Drying of Thin Materials in the Falling Rate Period of Drying. Journal of Engineering Physics and Thermophysics, 93, 364–368. https://doi.org/10.1007/s10891-020-02129-0.
16. Ol’shanskii A. I., Zhernosek S. V., Gusarov A. M. (2018) Experimental Studies of Heat and Moisture Exchange in the Process of Convective Drying of Thin Wet Materials. Enеrgеtika. Izvestiya Vysshikh Uchebnykh Zavedenii i Energeticheskikh Ob’edinenii SNG = Energetika. Proceedings of CIS Higher Education Institutions and Power Engineering Associations, 61 (6), 564–578. https://doi.org/10.21122/1029-7448-2018-61-6-564-578 (in Russian).
17. Franchuk A. U. (1969) Tables of Thermal Performance of Construction Materials. Moscow, Research Institute of Construction Physics Publ. 143 pр. (in Russian).
18. Blazi V. (2005) Construction Physics: Designer’s Handbook. Moscow, Tekhnosfera Publ. 536 (in Russian).
19. Grigoriev I. S., Meimekhov E. Kh. (eds.) (1991) Physical Quantities. Moscow, Energoatomizdat Publ. 1232 (in Russian).
20. Kolesnikov P. A. (1965) Thermal Protection Properties of Clothing. Moscow, Legkaya Industriya Publ. 337 (in Russian).
Review
For citations:
Ol’shanskii A.I., Kotow A.A., Kuzmenkov S.M. Temperature During Convective Drying of Thin Flat Wet Materials. ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations. 2024;67(6):516-529. (In Russ.) https://doi.org/10.21122/1029-7448-2024-67-6-516-529
Views:
251
Email this article 