关键词: 关键词：气体渗透系数, 流速, 马尾松, 边材, Kruskal-Wallis 检验

Abstract:

Abstract: Longitudinal air permeability of Masson Pine ( Pinus massoniana ) specimens was determined at different flow rates from 1.3×10^-6 to 1.0×10^-5 m³•s^-1. The flow rate exhibited a linear and nonlinear relationship with the pressure difference between the ends of specimen within the investigated range. The nonlinear flow component increases with increasing of pressure difference or flow rate. The flow rate (or the pressure difference) had influence on the measured values of the longitudinal air permeability of each specimen. Of six investigated specimens, the relative difference between the maximum and minimum of the longitudinal air permeability was from 3.1% to 5.7% for five specimens, while one specimen had the relative difference as high as 34.2%. It suggested that measurement of air permeability of specimen should be made at different flow rates. Air permeability of wood should be taken from arithmetic or weighed average of values from measurement at different flow rates or different pressure differences. Moreover, the range of flow rates or the pressure differences should also be presented together with the air permeability of wood.

Key words: Key words: gas permeability, flow rate, Masson Pine( Pinus massoniana ), sapwood, Kruskal-Wallis testperties