Application of Axial Flow Pump System for Improving Urban Hydro Environment

Social development is increasingly demanding the improvement of urban hydro environment, which depends on the improvement and maintenance of water quality. These are inseparable from pumping to provide certain hydrodynamic conditions to maintain the flow and renewal of water. The lifting head of such pumping stations is usually very low, generally around 1.0m, which has special requirements for the pump system. A new micro-lift horizontal axial flow pump system is proposed, which provides enough hydrodynamic conditions for urban hydro environment improvement and is well applied. The traditional elbow is optimized and analyzed by CFD numerical simulation of the entire passages flow of the system. The results show that the system has good flow characteristics, and the axial velocity uniformity of the outlet section of the suction passage at different flow rates is above 96%; the highest efficiency of the pump system is predicted to be 77.2%. A model test of the pump system was performed on a hydraulic machinery test system to verify the numerical results. At the different blade angles of 2°, 0° and 2°, the head is between (1.6-1.9) m and the highest efficiency is 78.1%, which meets the requirements of practical applications. The horizontal shaft extension pump system has been successfully applied in a pumping station in Yangzhou City, Jiangsu Province. The field test of the pumping station shows that the hydraulic performance of the prototype S-shaped shaft extension pump system is basically consistent with the performance results of the model test. The pump unit operates stably with low vibration and low noise. The high-efficiency shaft extension pump system has a simple structure, a compact layout, a large working space, and convenient installation and maintenance. Because the hydraulic loss of the system is significantly reduced, the operating cost of the pumping station is relatively low, especially for the long-running pumping station, which is obvious in energy saving and consumption reduction; it is suitable for small and medium-sized pumping stations and can implement standardized construction.

Key words: Axial flow pump; shaft extension; s-shape; flow field; performance