透過率測定による充てん構造の決定

抄録

Bader¹⁾ proposed an empirical equation (1) based on the measurements of air permeability of snow. A large portion of this report is concerned with the meaning of the parameters a and ε0 in Bader's formula.
Our purpose has been to measure the permeability of various packings and to determine whether the parameters obtained from the permeability measurements could be used to define the type of the packings.
It has been found that Eq. (1) has general application to homogeneous and heterogeneous beds of powders of various materials, sizes and shapes. The parameter a for the same powders is constant not influenced by the structure of beds, and the relationship between a and the mean volume-surface diameter d is expressed by the Eq. (3). The parameter ε0 of homogeneous beds is found to increase with decrease in the particle size below a critical diameter concerned with the materials and the shapes, and for the particle sizes greater than the critical diameter it is constant. The differences in the value of the constants for the different powders appear to depend chiefly on the particle shape. For mixtures of powders of two or three different sizes ε0 is smaller than that for onecomponent systems. For the beds with aggregates in it ε0 is smaller than that for the homogeneous beds, and for the beds in which two layers of different porosities are piled up ε0 is greater than that for the homogeneous beds.