The volumetric concentration of solid particles in pipeline was measured by a concentration meter of horizontal U-pipe type installed on the way of 2-inch pipeline of testing apparatus.
Flow of solid-water mixture in a bend composing the horizontal U-pipe was considered. As a result it may be thought of that information obtained from the concetration meter of this type having four bends equals to approximately that obtained from. the meter of horizontal straight pipe type.
Samples of the solid particles were fine gravel, coarse sand, fine sand and coal of mean size 10.5mm.
The ratio of the volumetric concentration in the pipeline to the deri vered volumetric concentration Cv
i/Cv
owas studied in relation to Froude pumber vw
2/{gD (s-1)}.
In a given sample, the ratio Cv
i/Cv
owas a constant independently to Cv
oin the range from 6 to1 5 of the Froude number, therefore the authers' experiment gives support to a result of R.C.Worster and D.F.Denny.
Although Worster and Denny gave Cv
i/Cv
o=1.13, it seemsto be particular value. Our experiment indicated that the ratio Cv
i/Cv
o was proportional to nondimensional group (v
f√gD) In (D/d
s) in the range of the Froude number, where vf is the mean free settling velocity of the solid particles, D is the pipe diameter, ds is the mean diameter of the solides particles and g is the acceleration of gravity.
The nondimensional group (v
f√gD) In (D/d
s) may be regarded as a criterion of easiness of horizomtal hvdraulic transportation of the solid particles in the heterogeneous flow without deposision. The solid sample which thenomdimensional group gives a small value will be transported more easilythan in case of a large value.
Furthermore, the ratio of difference between the mean velocity of water and the mean velocity of the solid particles to the mean velocity of water (vw-vs)/vw was compared with another nondirhensional group (v
w-v
s) 2/{gD (s-1)}.As a result, it was shown that the ratio (v
w-v
s)/vw has a minimum value in horizontal transportation in a pipe.
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