石炭の流体輸送に関する研究 (1)

浮遊速度に関する理論的ならびに実験的研究

抄録

In the present study, the outhors considered the settling velocity of spherical material in the vertical pipe by changing the diameter of the material.
From the results of this studies, the following conclusions were obtained.
(1) Equilibrium equation of material was expressed as
π/6d³γe/g dVe/dt=π/4d²CDγω(Vωm-Ve) ²/2g-π/6d³ (γe-γω) +2λζπ/4d²γω(Vwm-Ve) ²/2g
where Vc=raising velocity of material cm/s
Vwm=mean velocity of water along the material cm/s
CD-drag coefficient
λ=frictisnal coefficient between material pipe and water
λc, λω=weight pef unit volume of material and water respectively
d, D=diameter of material and pipe respectivelly
ζ=coefficient about d/D
=1+2a²/4a (1-a²) +3√1-a²/4 (1-a²) ²tan^-1a/√1-a²+π(1-a²/4)(1-√1-a²) √1-a²/2 (1-a²) ²
(2) Settling velocity Vf was expressed as
Vf=σf√4gd (ρ-1)/3 cm/s
σf√1-a²/CD+2λζ
where σf=settling velocity coefficient
ρ=specific weight=γc/γω
α=rate of d and D
Then we ascertained that the theoretical value about the settling velocity of spherical material (ρ≅1.40) was very coincident with the value obtained from the experience.