A Simulation Study of the Heat Balance of Concrete Pits During Boiling of Non-Frozen Logs

Abstract

This paper presents an approach for computing the heat balance of boiling pits during the plasticizing of non-frozen logs intended for the production of peeled veneer. With the help of our non-stationary model, the heating times of beech logs with a diameter of 0.4 m, an initial temperature of 10°C, and a moisture content of 0.6 kg∙kg^-1 were determined at water temperatures in the pit equal to 70, 80, and 90°C. Using the determined logs’ boiling durations and the mentioned approach, the change in the total energy required to carry out the entire boiling process and that required for each of the individual components of the heat balance was calculated. Computer simulations were conducted for a concrete pit with overall dimensions of 8.0 × 2.6 x 2.5 m, a working volume of 20 m³, and a degree of filling with logs equal to 45, 60, and 75%. It was found that the increase in the water temperature from 70 to 90°C causes an increase in the total specific energy, as well as in the energy for the heating of the logs themselves, the construction, and the water of the pit. At the same time, the energy required to cover the heat losses of the pit decreases and the energy for heating the metal heater/radiator itself does not change. A decrease in the degree of filling of the pit with logs from 75 to 45% causes an increase in both the total energy and all its components except the energy for heating the logs, which remains unchanged.