Effect of local pipe bends on air-lift pump performance

In order to explore the mechanism of local pipe for affecting pump performance, from the point of flow pattern, the flow pattern, water flux and lifting efficiency are tested by changing air flow rate and submergence ratio. The test results clearly show that the style of pipe in the air-lift can hardly affect the flow pattern, but it has great effect on the pump performance. The water flux and efficiency in all cases increase with the increasing air flow rate, reach the peak, and then decrease. But at a certain air flow rate for the considered submergence ratio and water flux, the highest efficiency can be found. It is indicated that the water flux and efficiency is appreciably reduced when the pipe bend is installed above the gas injector. In addition, a model which described the promotion efficiency in the lifting pipe was proposed.