This was an investigation of the characteristics of an air-lift pump system for conveying solid particles. The experiments used vertical pipes of the following dimensions: 26mm I.D.×7.86m (L) and 40mm I.D.×7.86m (L). The solid particles were spheres of uniform sizes: 6mm or 10mm diameter. The working fluids were air and water. The ranges of the variables studied were as follows: submergence ratios were 0.6, 0.7 and 0.8; volumetric flux of air was from 0.1 to 12.3m/s; volumetric flux of solid particles was from zero to 0.14 m/s; particle density was either 2540 or 3630kg/m³. The investigators used a momentum equation to correlate the discharge flow rates of the solid particles and water with the supplied air flow rate. This report presents the comparative data and calculations.

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In this paper, the relationship between pressure fluctuation and the fluctuation of an in-situ solid concentration in solid-liquid two phase flow in a horizontal pipe was investigated. Fluctuation of the in-situ solid concentration and pressure fluctuation increased in relation to additions of the solid concentration. However, these fluctuations decreased, when beyond 10% of solid concentration was added at lower velocities. This appears to be due to a change of the dune shape from triangular to becoming flattened. The correlation coefficient between the fluctuation of the in-situ solid concentration and pressure fluctuation was calculated. The. absolute value of correlation coefficient was small at higher velocities, but on the other hand, it was large at lower velocities because of the movement of dunes, formed at the bottom of the pipe. The propagation velocities of fluctuation of the in-situ solid concentration were obtained from cross correlation function, and were compared with the dune velocities measured in the previous work. As the agreement was satisfied, it was confirmed that the propagation velocity of fluctuation of the in-situ solid concentration was approximately equal to that of the dune velocity, and was obtained through cross correlation function.

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An optical measuring system was developed to investigate the thin liquidsheet jet wave motion which takes place during liquid atomization. This system wascomposed mainly of three new measuring devices; a gradient measuring device for theobservation of wave mode and wave growth process, a velocity measuring device for themeasurement of wave and droplet velocity, and an amplitude measuring device for themeasuremnt of the wave growth rate. It was e found that after analyzing all of the datasystematically, this measuring system proved useful in evaluating the behavior of theliquid sheet. As a result, the flow motion of the thin liquid sheet in a gas stream, includingthe wave mode near the nozzle and the wave growth process, was experimentally clarified.

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Two Phase flow experiment was conducted using a 300mm diameter, 100m long straight pipe with adjustable gradient. A cast-iron with, in part, transparent plasticpipe was used. Superficial water and air velocities were somewhat low, ranging from 0 to 3m/s and 0 to 20m/s. The data show scattering by intermittent flow to beunstable. Test results are as follows
1. Observed flow pattern in the horizontal pipe shows that the boundary betweenintermittent flow and separate flow is almost the same as that of lately publishedresults. But flow pattern is much more sensitive to pipe gradient, with a degree of 1/1000. Down gradient flow shows a wide separated pattern and the up gradient flowshows intermittent flow throughout almost all the area.
2. The void ratio is also sensitive to pipe gradient. In horizontal and up gradient flow, voidratio seems to show similar value to when the ratio of superficial air velocity to superficialwater velocity is equivalent.
3. Empirical formula of the pressure loss at various superficial water and air velocitieswas obtained.
4. Empirical formula of the effect of the pipe gradient on the pressure loss wasachieved. Tests will be carried out successively to gain further information.

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