希薄高分子溶液中を沈降する粒子の抗力係数
1984 年 100 巻 1151 号 p. 29-34
詳細
1984 年 100 巻 1151 号 p. 29-34
In the course of research on the application of the Toms' effect to hydraulic tansportation of solids, it was necessary to determine the drag coefficients of sand particles in the dilute polymer solutions.
During the measurement of free-settling velocity of sands, it was observed that the drag coefficient of a particle in the dilute solutions of polyethylene oxide (PEO) is larger than the one in the fresh water.
In the range of sphere Reynolds number from 1 to 1000, as the concentration of polymer solutions and/or the molecular weight of polymer increase, the difference of the drag coefficients between in the PEO solutions and in the fresh water increase.
Using the mean square radius of gyration and the distance between molecules in the PEO solutions, the correlation of the settling velocities is formulated as follows:
vp/vw=0.1045 (l)/2 (S) 3.12·(2 (S)/d) m
where m=0.748 log (d/2 (S))-0.2352.
vp=settling velocity of sphere in polymer solution, vw=settling velocity of sphere in fresh water, d=diameter of sphere, (S) =mean square radius of gyration of polymer in solution, 1=distance between molecules in polymer solution.
Therefore, the drag coefficients and the Reynolds numbers in the dilute polymer solutions can be calculated from that in Newtonian fluids and the above formula.
