Nonisothermal moisture movement in wood
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摘要: 为研究微波真空等高强度干燥过程中，温度梯度对木材中水分迁移的影响程度，该文通过试验测定了封闭马尾松木材试件在短期温度梯度作用下，木材内部温度场和含水率场的分布，含水率梯度与温度梯度比值的大小(dM/dT)及其影响因素.试验结果表明:在短期温度梯度的作用下，木材内部的水分会从热端向冷端迁移，使冷端的木材含水率高于热端，形成方向相反的温度梯度场和含水率梯度场，且dM/dT在0.9%/℃以下；木材内温度、初始含水率和作用时间是影响dM/dT的重要因素；随着木材温度和初始含水率的增加，木材中的dM/dT越大；随着作用时间的延长，木材中的dM/dT增加。Abstract: In order to study the effect of temperature gradient on moisture movement during high intensive drying such as microwave-vacuum drying, the authors measured the temperature and moisture content profiles in sealed wood whose opposite faces were subjected to temperature gradient for a short time.Then the absolute value of the ratio of the moisture content gradient to the temperature gradient(dM/dT) was calculated. The initial moisture content, temperature range and experimental period are all important factors affecting the experiment. The results indicated that moisture fluxed into the wood from the warm surface to the cold one even if opposite faces of the sealed wood assembly were exposed continuously to different but constant temperatures for a short period, the moisture content in cold surface was higher than that in the warm face, the moisture content gradient opposite to the temperature gradient was established, and the dM/dT is below 0.9/℃. Some factors, such as experimental time, temperature and initial moisture content in wood, had significant effects on dM/dT, which was found to increase with these factors。
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期刊类型引用(5)
1. 刘纪建，张倩倩. 基于非稳态法测定木材水分扩散系数. 林业与生态科学. 2018(01): 64-68 . 
百度学术
2. 张存猛，朱代根，殷昕. 木材热处理过程中的热质传递研究进展. 林业机械与木工设备. 2016(12): 7-9 . 百度学术
3. 李文军，李贤军，张璧光. 刨花对流干燥过程的数学模拟. 北京林业大学学报. 2009(S1): 99-103 . 本站查看
4. 李贤军，张璧光，李文军，周永东. 木材微波真空干燥过程的数学模拟. 北京林业大学学报. 2008(02): 124-128 . 本站查看
5. 李贤军，吴庆利，姜伟，张璧光. 微波真空干燥过程中木材内的水分迁移机理. 北京林业大学学报. 2006(03): 150-153 . 本站查看
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