Experimental investigation of air lift pump

Abstract

Air lift pump has been predominantly used for lifting of waste-water, aggressive fluid, transportation of solids and radioactive fluids in nuclear recycling plants and also for deep sea mining. The air lift pump performance depends on some fluid and geometric properties. Experiments were carried out by setting up a model air lift pump to unearth some of these parameters and their influence on the performance. Thereafter a Lift Dimensionless Number (LDN) and Pump Dimensionless Number (PDN) were derived to capture all the flow parameters. Using the experimental  results obtained a logarithmic plot of the dimensionless numbers was obtained to established a relationship between the dimensionless numbers. It was generally observed that air lift pumps with smaller riser pipe diameters yielded higher lifts. From the experiment it was also noted that fluid with better adhesive properties (e.g. water) produced higher lifts. For all cases of injection pressures for different fluids and mixture of fluid and solid, the lift increased with increasing submergence. A logarithmic plot of LDN against PDN yielded a slope 0.22 and intercept -0.78. The study has therefore been able to generate dimensionless parameters for characterizing the lift pump.