Experimental Study of Airlift Pump Performance with S-Shaped Riser Tube Bend

Airlift pump is a type of deep well pu mps. Somet imes, it is used for removing water fro m mines or pumping slurry of sand and water or other solutions. The performance of airlift pu mp is affected by two sets of parameters; the geo metrical and operational parameters. The geo metrical parameters include p ipe diameter, pump height, design of air in jection system, and entrance geometry of the lift ing pipe; while the operational parameters involve submergence ratio, conditions of injected air, and nature of lifted phase. Conventionally, airlift pump with bent riser tube is less efficient than that with vertically straight riser tube. However, in real life situations, the use of local riser tube bend or flexib le riser tubes is considerably unavoidable. This work investigates experimentally the effects of local bends of the riser tube on the airlift pu mp performance. A series of experiments on a model airlift pu mp with three d ifferent riser tube configurations, based on the vertical position of local bends, were carried out. The local bends are in the form of an S-shaped like duct. The results showed that setting local bends of the riser tube near the air inject ion zone improves the airlift pump performance. However, imp rovement obtained in airlift pump performance is being negligible and, thus, the position of local bend of riser tube does not contribute to improvements in the perfo rmance of airlift pump.