粉体層の構造因子と毛管力
1982 年 98 巻 1137 号 p. 1147-1152
詳細
1982 年 98 巻 1137 号 p. 1147-1152
Capillary potentials of granular beds were determined by two methods, measuring the equilibrium height of capillary rise into a vertical sample column and measuring the pressure necessary to force air through liquid saturated particle beds. Granular materials used were glass beads, abrasive fused alumina and sand.
From analogous definition of the hydraulic radius for the particle beds. It follows that for the equilibrium height hf or entry pressure Pe,
pghf=Pe=6 (1-e)γcos θ/(e ds)
Where ds is the specific surface diameter, e the void fraction, g the acceleration of gravity, γ the surface tension of liquid, θ the contact angle, p the density of liquid.
This equation was derived from energy change accompanying capillary rise of liquid.(Minimization of the potential energy due to the force of grabity and the surface tention.)
Experimental results for the sample materials was substantiated by the equation with ds obtained by a permeability method. The values of constant in the equation were estimated to be 5 from the height of rise measurements and 6 from entry pressure measurement. It should be emphasized that granular beds showed a large capillary hysteresis.
