木材解吸过程中含水率及温度变化的研究

The Variation of Moisture and Temperature in the Internal of Wood during Desorption Process

以尺寸20 mm ×20 mm× 10 mm的杨木为试材,利用自行研制的恒温箱、配合红外热像仪考察了在25℃,从相对湿度100％调节至22％、47％和75％3种条件下解吸过程中试材的含水率、温度变化及其顺纹方向上的温度梯度分布情况.结果表明：在解吸初期,试材的含水率迅速下降,其整体平均温度也明显降低1～5℃;随着解吸过程的进行,木材含水率和整体平均温度逐渐趋向平衡;在顺纹方向上,试材的温度呈现出表面温度低、中间温度高的分布形态,表层与芯层之间的温度差在解吸过程初期5 min内达到最大值,约为0.7℃,当达到解吸平衡时二者之间的温差约降至0.2℃.

Desorption processing of poplar（Populus euramericana Cv.）with size of 20 mm × 20 mm × 10 mm were investigated from 100％ to 3 different relative humidity conditions of 22％,47％,and 75％ at 25℃.A self-designed temperature chamber was used in order to take thermal images at a certain time intervals during the processes.The results showed that with the moisture content of the specimens decreased,the average temperature were also reduced of 1-5 ℃ at the beginning of desorption process.During the desorption process,the moisture content and average temperature of the specimens was gradually approaching the equilibrium state.The temperature for center layer along the longitudinal direction of the specimens was higher than that for surface layer.The temperature difference between the center and surface reached the maximum value of 0.7 ℃ at the first 5 min and eventually reduced to 0.2 ℃ at equilibrium state.