Internal Flow Analysis And Performance Prediction Of Tubular Pump With Adjustable Rear Guide Vanes

Tubular pump is widely used in high-volume and low-lift pumping station. Because of its superior flow capacity and high efficiency, in the south to North Water Diversion Project, the tubular pump system structure is used in the five newly built pump station. To further improve the efficiency of tubular pump, numerous experts and scholars are focusing on optimizing its hydraulic performance. Vane is a core device of the tubular pump, it’s main role is the diffusion of water, reducing the flow rate and energy recovery. However, due to the guide vane blades are fixed, in certain operating conditions, the effect of guide vane recycling circulation being poor, thus increasing the hydraulic loss, reducing the pump efficiency. Therefore, to carry out the internal flow analysis and performance prediction research of tubular pump with adjustable rear guide vanes, it has very important theoretical significance and engineering application value for reducing energy consumption, increasing the efficiency of the tubular pump and promoting the innovation and technological progress of pump station.The commercial CFD module of DM, TurboGrid and ICEM in the software of ANSYS were adopted in the modeling and meshing of tubular pumps inclusive of the water inlet pipe, impeller, guide vane, the water outlet pipe. The standard model of κ-ε was used to close the RANS equation, the generated grid were imported to the CFX software for pre-processing, numerical simulation of three-dimensional turbulence and post-processing. And the performance prediction of tubular pumps was done based on the simulation results.Firstly, the numerical simulation was carried out with 5 kinds of different grid numbers for meshing independent analysis to determine the suitable number of grids in numerical analysis, ensuring that the number of grids has no obvious effect on the results of tubular pump performance. Focus on the adjustable impeller and guide vanes of tubular pump, their regulation mechanism were analyzed, a simple and feasible mechanical gear-driven guide vane adjusting device was proposed.After the brief analysis of tubular pump with fixed guide vane, and on the basis of its internal flow field simulation and the hydraulic performance calculation of tubular pump, this paper analyzes the internal flow patterns, energy performance, guide vane hydraulic loss and recovery of circulation of the outlet section under different setting angle of guide vane to different setting angle of impeller, and it was compared with performance of tubular pump with fixed guide vane in the same working conditions, and it discussed the setting angle of guide vane on the impact of performance of tubular pump. The results show that the tubular pump with adjustable rear guide vanes has good hydraulic performance, when running under off-design condition, by adjusting the setting angle of guide vane, the hydraulic loss of guide vanes is small, the efficiency of tubular pump can be improved effectively: in the small flow rate condition, with the guide vane angle regulating to negative direction, tubular pump hydraulic performance becomes better; in the large flow rate condition, with the guide vane angle regulating to the positive direction, the hydraulic performance of tubular pump improves more evident.