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作 者 ：侯祝强 鲍甫成

期 刊 ：林业科学 1999年 35卷 3期 页码：63-68

关键词：木材流体渗透性；可压缩流体；粘性流；滑流；线性流；非线性流；

Keywords:Wood permeability, Compressible fluid, Viscous flow, Slip flow, Linear flow, Nonlinear flow,

摘 要 ：本文针对可压缩流体在木材中渗透时出现的粘性流、滑流与非线性流,根据木材解剖构造特性运用统计物理和流体力学有关理论,分析讨论了粘性流、滑流与非线性流产生的原因和机理,及其与木材中可压缩流体渗透性的关系。粘性流存在于木材中流体通过的所有孔隙,而滑流存在于木材中满足滑流产生条件的那部分孔隙中。在通常的渗透压强条件下Re≤10,木材中流体渗透的流动型态不存在湍流。流体动能损失导致的非线性流的出现,使可压缩流体的流动特性偏离达西定律,当使用Klinkenberg方程和Adzumi方程分析测量数据研究木材可压缩流体渗透性时,要注意非线性流的影响,降低渗透压强能减少或避免非线性流。木材可压缩流体渗透性与可压缩流体的流动型态间有一定关联。

Abstract:This paper studies the mechanism and origin of linear flow components (viscous flow and slip flow, or Knudsen diffusion) and nonlinear flow component, which occur in fluxes of the compressible fluid permeating through wood. The viscous flow exists in all the capillaries which the fluid flows through, and the slip flow only exists in those whose dimension of pore crosssection is equal to or less than mean free path of fluid molecule. Due to kinetic energy loss at the entrance and exit of a capillary, the nonlinear flow may be brought about when the compressible fluid permeate through wood. In case of the occurrence of the nonlinear flow, Darcy‘s and Poiseuille‘s laws are no longer applicable to the permeating flow. One must affirm whether there is the nonlinear flow and avert its effect on the permeability when calculating the wood fluid permeability and equivalent radius of the capillary by means of Klinkenberg equation and Adzumi equation with the measurement data. There is relationship in some degree between wood permeability to compressible fluid and flow pattern of the permeating fluid.

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