1.中国林业科学研究院木材工业研究所;国家林业和草原局木材科学与技术重点实验室,北京 100091
2.西昌学院,四川西昌 615000
3.国际竹藤中心;国家林业和草原局竹藤科学与技术重点实验室,北京 100102
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黄荣凤,高志强,冯上环等.含水率非均匀分布木材在热板加热下温度分布的变化规律[J].木材科学与技术,2023,37(01):40-47.
HUANG Rongfeng,GAO Zhiqiang,FENG Shanghuan,et al.Temperature Distribution in Wood with Uneven Moisture Distribution during Preheating Process by Press Platens[J].Chinese Journal of Wood Science and Technology,2023,37(01):40-47.
热作用下温度分布和含水率分布的变化规律，是实木层状压缩形成机制研究的基础。以初含水率处于非均匀分布状态下的毛白杨木材为对象，研究在180 ℃热板夹持加热过程中的温度分布变化规律，为揭示层状压缩形成机制提供科学依据。结果表明：初始含水率表层高、内部低的木材，在热板夹持加热过程中，厚度方向上始终存在一个明显的升温速率峰值。随着加热时间的延长，升温速率峰值和高含水率层逐渐向中心移动；高含水率区域内木材，温度较玻璃化转变温度高6.11~47.58 ℃，处于层状软化状态，是层状压缩形成的重要原因之一；采用多元线性回归分析方法建立的木材厚度方向温度预测多变量函数模型，决定系数为0.985，预测木材内部温度的标准误差为3.21 ℃，能够用于木材内部温度分布的预测。
The change in the temperature and moisture distribution in wood is the fundamental mechanism for solid wood sandwich compression formation. In this study, poplar (,Populus tomentosa,) wood with high moisture content (MC) on surfaces and low MC in the interior was used as the raw material. The poplar wood was preheated by press platens at 180 ℃, to investigate the changes of temperature distribution in wood during the preheating process in order to provide evidence for clarifying the mechanism for wood sandwich compression. It was found that a peak heating rate existed in the thickness direction all the time during preheating. As the preheating time extended, the peak heating rate migrated from wood surfaces to the center. The temperature of high MC area was 6.11~47.58 ℃ higher than the wood glass transition point and thus this area was being softened, which was one of the main reasons for wood sandwich compression formation. A multivariate functional model with a coefficient of determination of 0.985 was built to predict the temperatures along the wood thickness direction. The standard error for the predicted temperatures in wood was 3.21 ℃, suggesting that this model can well predict temperatures in wood.
含水率非均匀分布木材热板加热升温速率温度分布层状压缩
uneven distribution of MC in woodheating by heating platesheating ratetemperature distributionsandwich compression
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