木材干燥理论架构及其数学表达的研究简报

A Brief Report on Theoretic Framework of Wood Drying and Its Mathematical Expression

应用物理力学的理论方法,推导木材干燥过程中发生的热流、水分扩散流和渗透流与引起这些流的驱动力(温度梯度、湿度梯度和压力梯度)之间定量关系的热质耦合迁移定律。同时导出木材介质内部温度场和湿度场的非稳态偏微分方程组。由迁移定律和场方程共同构成一个完备的、严谨的木材干燥理论架构系统,为木材干燥等热加工处理工艺参数的制定与调控提供科学分析的理论依据。

Laws of coupled heat and mass transfer,which is about the quantitative relations between flux(i.e.heat flux,moisture flux,osmosis flux)taking place during the process of drying of wood and its driving forces(i.e.temperature gradient,humidity gradient,pressure gradient),were derived by means of physic-mechanics.At the same time,the general time-dependent partial differential equations on the fields of the temperature and the humidity in wood medium were developed from the above transfer laws with the help of some physical laws and mathematic methods.Then,a complete and rigorous set of new system of wood drying theory was composed of coupled heat and mass transfer laws and differential equations in the field of the temperature and the humidity.It provides a theoretical basis of scientific analysis for formulating and regulating technological parameters of wood drying or heat-treatment.