Improvement of the Analysis Technique of the Convective Lumber Drying Process

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UDС

674.047

DOI:

10.17238/issn0536-1036.2018.4.132

Abstract

The method of convective kiln drying is the most common technique among the various methods of wood drying. Modes regulate the lumber drying process depending on the spe-cies and the size of the time or wood moisture content. The Reference specification on the technology of kiln drying of sawn timber prescribes regimes in dependence on the wood moisture content. The drying schedule provides control of the initial lumber moisture content by sampling from different areas of the drying stack for weighing, determining the current moisture content and putting them back into the stack. However, this method of determining the current moisture content of wood requires the periodic opening of the working kiln (which changes the parameters of the drying medium) and transition to one of the three stages of the drying schedule. The drying process is characterized by increasing operating severity with a decrease in the moisture content of sawn timber. The drying schedule should ensure the shortest drying time while maintaining the natural properties of wood. The article considers the application of the analysis technique of the moisture content field of lumber, since the time-varying regimes do not provide accurate information on the expected state of moisture over time. The developed method for calculating of the moisture distribution in the cross-section of sawn timber using the finite-element method in the form of a set of triangles, global stiffness grids and resultant load vectors allows determining the moisture content at the grid nodes. A comparison of the drying curves determined by the P.S. Sergovskiy’s method and by the proposed method demonstrates the more accurate results of the second technique.

Authors

N.B. Balantseva, Candidate of Engineering Sciences, Associate Professor
V.I. Melekhov, Doctor of Engineering Sciences, Professor
O.A. Kalinicheva, Candidate of Engineering Sciences, Associate Professor

Affiliation

Northern (Arctic) Federal University named after M.V. Lomonosov, Naberezhnaya Severnoy Dviny, 17, Arkhangelsk, 163002, Russian Federation; e-mail: n.balantseva@narfu.ru

Keywords

convective lumber drying, Delaunay triangulation, Galerkin method, moisture content field, partial differential system, finite-element method, system of linear equations, moisture transfer equation

For citation

Balantseva N.B., Melekhov V.I., Kalinicheva O.A. Improvement of the Analy-sis Technique of the Convective Lumber Drying Process. Lesnoy zhurnal [Forestry journal], 2018, no. 4, pp. 132–139. DOI: 10.17238/issn0536-1036.2018.4.132

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Received on October 10, 2017