The Internal Flow And Performance Prediction Of Vertical Submersible Pump System

Cube-type bidirection passages of vertical submersible axial-flow pump system is a new type of pump system which combines cube-type bidirection passages with submersible axial-flow pump together.It has both the characteristics of cube-type bidirection passages and submersible axial-flow pump, the structure is simple and practical, good heat dissipation, low noise, and simplify the structure of pump station construction, etc. While the bidirection passages can both irrigate and drainage, it is appropriate for low-lift pumping station with the requirement of two-way water.At present, submersible axial-flow pump is usually used for one-way and horizontal pumping system, rarely used in two-way flow pump device. Research on optimizing the hydraulic design of bidirection passages of submersible axial-flow pump system is still in its infancy at home and abroad, so the hydraulic performance is lack of understanding.The numerical simulation was made based on a bidirectional pump station that will be updated.lt used standard κ-ε turbulence model and three dimensional Reynolds averaged navier-stokes equations, and used modules provided by the CFD analysis software ANSYS, such as DM, ICEM CFD, TurboGrid and CFX to complete the overall process of three-dimensional modeling, meshing, numerical calculation and post-processing of the calculation results.First of all, in order to understand the performance of the pump impeller and guide vane, the numerical simulation of the axial-flow pump section was performed based on the CFD technology. The highest efficiency of pump section was85%, which achieved similar performance levels to domestic axial flow pump. The performances of two guide vanes with different kinds of blade inlet angle were compared. When the head of pump section less than1meter,the efficiency was significantly higher as blade inlet angle of guide vanes increased. Second,internal flow field of cube-type bidirection passages of submersible axial-flow pump system,including suction passage, impeller, guide vane and discharge passage was numerical calculated, and the performances of the pump system were predicted.According to the hydraulic characteristics of the pump system, the effects of the anti-vortex lattices and flow guide pier on the performance of the pump system were analyzed. When the rate of flow is2701/s, the highest efficiency of submersible pump systems which set flow guide pier,no facilities, and the anti-vortex lattices are71.25%,72.38%and71.25%respectively. It was obviously that these measures have little impact on the efficiency of pump system, mainly in order to eliminate vortex, and guarantee the safe and stable operation of pump units. The internal flow of the diffusion guide vane was analyzed, It was compared that effects of hydraulic loss and the performance of the pump system on different leaf number of the guide vanes.In addition,the hydraulic performance of pump system which sets the division piers in discharge passage,the highest efficiency is71.12%. This measure cannot improve the flow state, but reduced the efficiency of pump system. The unidirectional pump system with the same in and out of type were also analyzed, its highest efficiency is72.05%, which had little difference with the bidirectional pump system, so cube-type bidirection passages of vertical submersible axial-flow pump system had great value in engineering application.