Optimizing Flow Conduit and Test Analysis of Axial Flow Pump Device in Siyang Second Station

Abstract

【Objective】 The purpose of this paper is to improve the hydraulic performance of the pump device in the reconstructed project of Siyang Second Station and clarify its hydraulic performance. 【Method】 Taking the vertical axial-flow pump device in Siyang Second Station as an example, the hydraulic performance of its original pump device was analyzed numerically, from which we optimized its inlet and outlet conduits. With D representing the nominal impeller diameter, the dimensions of the original elbow inlet conduit was: height, 1.707D, length, 3.895D, and inlet area, 4.984D2; the dimensions of the original siphon outlet conduit was: inlet diameter, 1.09D, length, 6.14D, outlet area, 3.934D2. The energy performance parameters of the pump device were obtained by physical model test. 【Result】 The optimization of the square rounded tapering geometric profile of the elbow section of the inlet conduit and the starting position and length of the outlet conduit pier is given. The uniformity of the axial velocity distribution on the outlet section of the optimized elbow inlet conduit increases by 3.32%, the weighted average deviation angle decreases by 0.945o, and the hydraulic loss decreases by 10.4%. Compared with the original scheme, the hydraulic loss of the optimized siphon outlet conduit reduces by 7.51%. When the blade angle +2°and the design lift 6.30 m, the flow rate of the prototype pump device is 35.2 m3/s, which meets the design flow requirements, and the efficiency is 76.02%. At the maximum lift of 6.8 m, the flow rate of the prototype pump device is 33.84 m3/s and the efficiency is 75.97%. When the average lift is 5.55 m, the flow rate of the prototype pump device is 36.58 m3/s, and the efficiency is 74.23%. 【Conclusion】 When the main control sizes of the inlet and outlet conduits are not changed, the inlet width of the elbow inlet conduit is only shortened to 2.2D, and the starting position of the siphon outlet conduit pier moves 0.772D to the outlet section and the pier head is perpendicular to the flow direction, the hydraulic efficiency of the pump device in the reconstruction project of Siyang Second Station is relative higher. It ensures the safe, efficient and stable operation of the reconstructed Siyang Second Station. The optimization strategy provides a reference for the reconstruction and optimization of the built pumping station.

Keywords

• axial-flow pump device
• flow conduit
• optimization
• hydraulic performance
• model test