With the increasing demand of small-flow and high-head pumps, vortex pump, which can be used in industry, agriculture, medical and aerospace etc., has become more and more popular as low specific pump. However, the pressure fluctuation of fluid in the vortex pump would cause flow noise and vibration which may result in damage to the equipment. Clearly, it is important to reduce the fluctuation causing by fluid flow as much as possible.
This study examined and discussed the law of pressure fluctuation in a micro vortex pump by the method of numerical simulation. In addition, a random distribution method was applied to design two new impellers with different blade spacing. Moreover, the influence on pressure fluctuation of different blade positions was predicted by theoretical analysis and CFD analysis.
The results show that the blade passing frequency is dominative in the pressure fluctuation. Although the average static pressure distribution on the circumference of the micro vortex pump increased gradually along inlet to outlet, the pressure pulse amplitudes were fluctuant and the maximum amplitude area was close to the stripper. Affected by the vortex motion in the pump, there were clutters in the spectrum from inlet to outlet even for the vortex pump with uniform circumferential blade spacing. The study also indicated that uneven circumferential spacing would yield additional frequency in the spectrum compared with even one and reduce the magnitude of the dominant frequency without decreasing the performance of the pump sharply.
Based on the consequence, this paper proves the feasibility of applying uneven blade spacing to reduce pressure fluctuation in a vortex pump. And it could be meaningful for the noise and vibration reduction as well as development of vortex pumps.
Relation between the Vortex Motion and the Pressure Fluctuation in a Plane Impinging Jet
