Abstract:

A mass of heat will be generated inside the wood by the direct interaction between microwave electromagnetic filed and water molecule or polar group in wood, which can be used to dry wood quickly or for the modification pretreatment of wood. Based on the physical law on heat transfer, a mathematical model to describe the temperature profiles of wood during microwave drying was established and simulated in this research. The results showed that the temperature profiles and its uniformity inside wood are dependent on the microwave heating methods during a microwave drying. The temperature inside wood gradually decreased along the direction of microwave transmission when the unilateral microwave heating was applied during wood drying, and the curve of temperature profiles along the thickness direction of wood is not flat. The temperature gradient with the interior temperature higher than the one in the surface layers was presented inside wood when the bilateral microwave heating were applied for wood microwave drying. Compared with the unilateral microwave heating method, the temperature distribution is more uniform along the thickness direction inside wood for the bilateral microwave heating.

Key words: microwave, wood, temperature distribution, simulation