石炭の流体輸送に関する研究 (第2報)

不規則形状体の浮遊速度ならびに上昇速度について

抄録

In this study, the author considered thefloating velocity (or settling velocity) and the rising velocity of a irregularly shaped material in the vertical pipe by using the various coals.
From the results of this study, the following conclusions were obtained.
(1) The floating velocity vf was expressed theoretically as
υ_f=c_a·υ_fsc_ac₀=f (d_e/D)/c_f·4√ι/d_e
(2) In the case of the coal cD·f (de/D) was obtained as follows,
cD·(de/D) = (1-de/D)
(3) It was ascertained that the solid materials of ordinary irregularity in shape as coal had the floating velocity of about 0.6-0.8 times that of the sphere same volume.
(4) The rising velocity ye was exprssed theoretically as
υc=cω'(υω-υ_f).
(5) From the experiments cw' was expressed as
cω'=e^0.642 (υ_ω/υ^f-1)
with the error ± 5% in the various coals.
(6) From the theoretical consideration the velocity coefficient c_w' was obtained as
c_w'=K/√cD+2λζ'
where above each notation is as follows,
υ_fs=floating velocity of asphere of the same volume
c_a=calibration coefficient
c_f=coefficient of the floating velocity of a sphere
l=maximum length of the material
d_e=equivalent diameter of the material
D=diameter of the pipe
cD·f (d_e/D) =the coefficient and the function determined from the experiments
υ_ω=velocity of water
c_ω'=veloCity coefficient
K, ζ'=constants determined from the sige and the shape of coal.
(7) The more the increase of the velocity of water υ_ω the less the drag coefficient cD and the apparent frictional coefficient λ, therefore the coefficient of the velocity c_ω' was not constant and increased.
This was the reason that the c_ω' was expressed as the above experimental equation.