Analysis of the Influence of Passage Components on the Efficiency of Bulb Tubular Pumps

For large discharge and low lift head, it is especially suitable to use tubular pumps for their economic characteristics. Tubular pumps have high efficiency, small hydraulic loss, compact unit structure, simple construction arrangement and low cost both for construction and running. Recently, in the east route of South to North Water Diversion Project in China, there are many low head and large discharge pump stations using tubular pumps. It is important to analyze the flow characteristics and performance of tubular pump. In this paper CFD method is used to simulate the whole flow passage in a bulb tubular pump which includes inlet passage, outlet passage, guide vane, bulb unit and supportings. Based on the RNG k–ε turbulent model with Wall-Function Law, the SIMPLE algorithm is applied for the solution of the discrete governing equations. The results of the calculation indicate that all of the flow passage components influence the efficiency of the tubular pump, especially the parts of guide vane unit and bulb section. The shape of the bulb and relative position of guide vanes and bulb supportings have important effects on total hydraulic losses of the pump. Reasonable supportings not only improve the turbulent flow, but also reduce circumference velocity. The efficiency of the pump after improving can be increased about 6%.