砂粒子の水平管水力輸送における水頭損失の低減について

トムズ効果を利用した固体粒子の水力輸送に関する基礎的研究 (第2報)

抄録

This paper described about the drag reduction effect of injecting the solution of polyethylene oxide (PEO) through avpipe-wall slot injector set up in the upper stream of test section of a horizontal pipeline, transporting water or water-sand mixture; the test section is a polyvinyl chloride clear smooth pipe 7.0m long and 2.5cm of internal diameter.
The maximum drag reduction in the flow of dilute water-polymer solution made up by injection is observed larger than the one of the like solution made up before hand in a head-tank.
As for sands the authors used Toyoura sand, Chikugogawa medium sand and Chikugogawa coarse sand, the average particle diameters of these sands are 0.207mm, 0.62mm and 1.29mm respectively.
The relative hydraulic gradient reduction in the pipe flow of sand-water-PEO mixture ranges from 35% to 70%, where the volumetric. concentrations of sands 5% to 20%, the average velocities 3.0m/sec to 5.5 m/sec, and the concentrations of PEO in aqueous solution 40 ppm to 60 ppm that seems to bring about the saturation of the Toms' effect.
The head loss for the pipe flow of sand-water mixture injected PEO solution might be expressed as follows:
_??_I_WSP=head loss in unit length of horizontal pipe, sand-water-PEO d mixture, I_WP=head loss in unit length of pipe, PEO solution only, C_V=volumetric concentration of sand, U_M=mean velocity in pipe, C_D=drag coefficient of sand in dilute water-PEO solution given by settling test of sand, S=specific gravity of sand.