Influence of stator vane number on performance of the axial-flow pump

The interplay of impeller and stator is investigated for an axial-flow pump. Three stator vane numbers of 5, 7 and 9 are devised to match the same impeller. The renormalization group k-e turbulence model is used to simulate three-dimensional flows in three pumps with different vane numbers. Axial velocity distributions at impeller outlet and stator outlet are comparatively analyzed. Experiments assess operation performance of the three pumps. Vibration parameters and static pressure fluctuations are measured as well. It is indicated that the influence of vane number on both pump head and pump efficiency is insignificant. Large stator vane number contributes to the improvement of the uniformity of axial velocity distribution at impeller outlet. At stator outlet, similar tendency is revealed. Severe vibration occurs near the outlet bend of the pump, as is particularly remarkable at vane number of 9. For the three cases, blade passing frequency and its harmonics are predominant in the frequency spectra of pressure fluctuations. As flow rate increases from 0.8Q to 1.0Q, high-frequency pressure fluctuations are suppressed considerably at vane number of 9, while the other two cases also manifest a decline in overall pressure fluctuation amplitude. The 7-vane case is the most preferable one among the three cases in terms of both pump performance and pressure fluctuation between the impeller and the stator.