用偏差活化能方法分析研究木材的干燥特性

偏差活化能可以表示被干燥物料的传质传热特性.通过理论分析和实验,该文研究了木材的不同几何尺寸与其偏差活化能的关系.基于木材的湿基试样之上,首先得到不同几何尺寸的木材的干燥率实验数据,然后建立模型计算扩散系数和偏差活化能.研究结果表明,不同几何尺寸木材试样的偏差活化能值随着环境温度和湿度而变化,并且影响着木材的传质传热动态特性;被干燥物料的偏差活化能在其几何尺寸较小时变化微小,并且随着尺寸的变小偏差活化能也下降;当干燥温度上升时,相对偏差活化能很快接近1,反之亦然.这些研究结果为进一步研究木材的动态干燥特性奠定了基础.

Drying characteristics of wood in different sizes using the method of apparent warp activation energy

The relationship between apparent warp activation energy and different dimensions of dried wood was investigated both theoretically and experimentally. Through changing the geometrical dimensions of wood based on the wet base, the rate of water evaporation with time was studied, then the diffusion coefficient was computated and the test data with their apparent activation energy were discussed. The results show that different dimensions of dried wood display different warp activation energies which vary with surrounding drying parameters such as humidity and temperature, and affect the properties of heat and mass transfer of the material. The apparent warp activation energy of dried materials change lightly in the drying process when the size of test samples is small, and will decease while the size of materials reduces. The relative apparent warp activation energy will approach the value of 1 rapidly while drying temperature rises, and vice versa.