微波处理中木材内温度分布的数学模拟

从热传导的物理规律出发,建立微波加热过程中木材内部热传导模型,并通过理论模拟揭示不同微波加热方式对预处理中木材内部温度分布的影响规律。结果表明:微波处理过程中,木材内部的温度分布规律及均匀性与微波加热方式直接相关;当采用单向微波辐射的方式进行加热时,沿着微波入射方向,木材温度逐渐降低,木材内部温差较大,且温度分布均匀性较差;当使用双向微波辐射的方式进行加热时,木材内能形成内高外低的温度梯度,且温度分布均匀性较好。

Mathematical Modeling of Temperature Profiles in Wood During Microwave Heating

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.