On the Performance of Air-Lift Pumps: From Analytical Models to Large Eddy Simulation

The present study investigates a hierarchy of models for predicting the performance of air-lift pumps. Investigated models range from simplified one-dimensional analytical models to large eddy simulation (LES). Numerical results from LES and from two different analytical models are validated against experimental data available from the air-lift pump research program at Alexandria University. Present LES employs the volume of fluid (VOF) method to model the multiphase flow in the riser pipe. In general, LES is shown to provide fairly accurate predictions for the air-lift pump performance. Moreover, numerical flow patterns in the riser pipe are in good qualitative and quantitative agreement with their corresponding experimental patterns and with flow pattern maps available in the literature. On the other hand, analytical models are shown to provide results that are of surprisingly comparable accuracy to LES in terms of predicting the pump performance curve. However, due to the steady one-dimensional nature of these models, they are incapable of providing information about the different flow patterns developing in the riser pipe and the transient nature of the pumping process.