COMPUTATION OF THE 2-DIMENTIONAL TRANSIENT TEMPERATURE DISTRIBUTION AND HEAT ENERGY CONSUMPTION OF FROZEN AND NON-FROZEN LOGS

摘要

A summarized 2-dimensional mathematical model has been created, solved, and verified for the transient non-linear heat conduction and energy consumption in frozen and non-frozen logs at arbitrary, encountered in the practice initial and boundary conditions. The model takes into account for the first time the fiber saturation point of each wood specie and the specific heat capacity of the wood itself and the ice contained in it, which has been formed from the freezing of the free, as well as of the hygroscopically bounded to it, water. It has been solved with the usage of an explicit form of the finite-difference method, where the distribution of the temperature field in all points of the volume of the log is calculated for the first time only with one system of equations. The paper presents solutions of the model, which prove the applicability of Fourier's criterion for similarity from the theory of heat transfer for the calculation of the heating of the logs. At different diameters of the logs andidentical relations of their lengths to their diameters, the distribution of the temperature in their volumes and the consumed energy for their heating at given initial and boundary conditions turn out to be identical for one and the same relations of the duration of heating to the logs' diameters.