Flow Characteristics and Geometry Optimization for Double Suction Volute Pump

Abstract

In a single-suction centrifugal pump, the liquid directly flows into the impeller inlet of the pump. The positive pressure is obtained due to the centrifugal action of the pump and the water passes away the impeller via the veins. The impeller of the double suction pump allows the flow to draw through both sides and divides the flow interior the pump equally between the two eyes. This design of the double suction provides higher flows than a single suction pump and helps to rids of the axial forces on the impeller. In general, the double suction centrifugal pump is commonly employed in many industries because of its advantages namely; high lift and large flow. The suction performance of the centrifugal pump can be improved by using double suction instead of single ones. One possible modification is to cut off the circulation close to the impeller outlet of the double suction volute pump using the tongue at the blade end. To examine the tongue geometry at the blade outlet on the flow field of the double suction volute pump, the experimental results and validation of the simulation results are conducted. The model has 23.75 rpm of the specific speed, the impeller contains 6 blades and tongue height factor Ht has different values of 0.1, 0.2 and 0.3. The inner flow fields and features of the double suction volute pump with several tongue height at blade end are predicted and simulated using commercial code Fluent under Ansys Ver.17.1. The studied test rig for Double Suction Volute Pump with standard impeller and three impellers of different tongue height is constructed. The head, flow rate, and shaft power are evaluated for each pump configuration to show the effect of these tongue lengths on pump performance. The results show that, when adding tongue shape, with height ratio Ht=0.2, H increased by 2.7 m (12.27%), and η by (7.41%). The power consumption in the case of tongue height ratio Ht =0.2 approximately constant compared with the total energy consumption without tongue shape with no power saving. It is also found that a good agreement between the experimental performance curve and time average of the numerical results.