Research On The Influence Of The Change Of The Gaps Of Guide Vane And The Runner Chamber In The Mixed-flow Pump

Pump is a general machinery which has a kind of variety and wide application, so it is significant to improve the operating performance of the pump. Since the mixed-flow pump which is widely used in water supply and drainage industry and construction equipment has the characteristics of small footprint, small diameter, easy to start, simple structure, wide efficient area and high efficiency, moreover the performance and structure between centrifugal and axial flow pump compensates the shortcomings of both and has advantages of both at the same time, it is necessary to study how to make efficient, stable and safe operation of mixed-flow pump. Various gaps in the pump is one of the important causes of leakage losses and bad influence on the operating performance of the mixed-flow pump. Unreasonable gap value will result in unnecessary leakage losses and the vortex flow inside the fluid and so on, thereby affecting its operating performance. This paper will examine the effects of vanes of mixed-flow pump and the gap changes of runner chamber on operating performance.We designed the test program for the model of mixed-flow pump, and conducted the model installation and sensor placement. First we tested the efficiency, cavitation and pressure fluctuation properties of mixed-flow pump when the gap is0.15mm, then we made efficiency and performance tests when the gap is0.25mm0.3mm by adjusting the position of bearing component to change the gap between blade tip and the runner chamber. Efficiency and performance tests for the changes of gap revealed that:when the gap is0.15mm at the design point Q’-354.31/s, the efficiency is83.74%, the head is7.955m, the shaft power is32.73kW; when gap is0.25, the efficiency is83.13%mm, the head is7.907m, the shaft power is32.35kW; when the gap is0.3mm, the efficiency is82.49%, the head is7.849, the shaft power32.11kW. The test results show that the larger gap between between blade tip and the runner chamber, the worse efficiency and performance the mixed-flow pump gets.On the basis of the model and the physical model tests, this paper made numerical simulation analysis on the gap changes of mixed-flow pump. First we established the physical three-dimensional model with Pro/E, and then used the ANSYS ICEM CFD to mesh the three-dimensional model, finally made solution and analysis for the model with the ANSYS FLUENT. We selected the design point354.31/s, made simulation of efficiency and performance for the gap of0.15mm,0.25mm and0.3mm, and made simulation of cavitation and pressure pulsation performance for the gap of0.15mm and0.25mm. The simulation results also show that:when the gap is0.15mm, mixed-flow pump gets higher operating efficiency and better cavitation performance and stability.