An experimental study on lab scale air-lift pump flowing solid-liquid-air three-phase mixture

A lab-scale air-lift pumping system with 3.64 m straight pipe is designed and manufactured to analyze and understand operational performance and characteristics of the air-lift pump. The experiments for air-liquid-solid three-phase flow in vertical pipe are performed by systematically changing experimental parameters, such as air injection rate, air injection points, pipe diameters, solid particle size and density, and solid injection rate. From the experiments, it is confirmed that the variables, such as superficial velocity of seawater and solid particle, in-situ velocity and volume fraction of solid particle in the suction pipe, and pumping efficiency, are inevitably affected by these parameters. An Optimization of these parameters is necessary to design and operate such a system adequately. Also, the effect of air-injection point rather than submergence ratio on the small-scale air-lift pump can be examined and the optimum efficiency of gas-liquid-solid 3-phase air-lift pump by extending the theory of gas-liquid 2-phase air-lift pump can be obtained.