回転板上の粒子層内流動

抄録

When a particles bed packed in a cylindrical vessel was imposed on a centrifugal force field by rotating a horizontal disk at the bottom of the bed, the flows are in vortex motion except in the case of sticky bed. The authors studied such flow property.
The experimental results and the dimensional analysis give the following dimensionless expression.
[Pg_c/nD⁴ρg]=Kμ'[h/D][ρnD²/μ]^a[Dn²/g]^b
where the left side term in parenthesis is the ratio of the drag force to the gravitational force, and in the right-hand terms K is a constant, μ' the dynamic friction coefficient between the bed and the disk's surface, the third term in parenthesis is the shape factor, h, the depth and D, the diameter of the bed, the fourth and the fifth terms are the Reynolds and the Froude numbers, respectively. As to the values of two constants a and b, a is -1/6 and b is 1/3 in the case of a typical dry operation, and they become -1/3 and 2/3, respectively, in case that water is added in amount to fill the voids of the bed.
This flow pattern seems to be effective for application in size reduction or mixing, because it gives strong centrifugal and shearing forces, but does not require such large power to be fed.