Influence of Prewhirl Regulation by Inlet Guide Vanes on Cavitation Performance of a Centrifugal Pump

The cavitation performance of an axial flow pump with inlet guide vanes for different flow rates is studied in this article. The effects of inlet guide vanes on pump hydraulic performance and cavitation are investigated, where the total vapor fraction of impeller zone (F tv ) is calculated to predict the critical net positive suction head, which is compared with that predicted by efficiency criterion for different flow rates. The influences of the development of cavitation on internal flow in impeller zone are also investigated. The results obtained show that the cavitation performance of axial flow pump can be improved at off-design flow conditions by adjusting angles of inlet guide vanes to positive values at low flow rates and by regulating angles of inlet guide vanes to negative values at high flow rates. As the net positive suction head decreases, the vapor fraction first increases slowly and then increases greatly, clearly presenting cavitation process from inception to full development, which can be used to predict the required net positive suction head. When net positive suction head decreases to the value around required net positive suction head, the cavitation zone from tip of blade suction side close to leading edge and the cavitation zone from hub part of the blade suction side connect together. After the connection, the cavitation zones have great influence on the velocity flow, leading to the decrease in pump performance.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Simulation of cavitation performance of an axial flow pump with inlet guide vanes

Feng

Cheng

Guo

2016

“…15 Backflow phenomena is always observed at the inlet when the pump operates at small mass flow rates, which may disturb the surrounding flow field and cause vibration and noise problems. 16 Import pressure at the inlet is an effective way to control the backflow.…”

Section: Numerical Simulation Of the Influence Of Jetting Equipment Omentioning

confidence: 99%

Investigation on the influence of jetting equipment on the characteristics of centrifugal pump

Yuan

et al. 2016

To reduce radial noises from the motor of centrifugal pumps, this study designed a water cooling system called jetting equipment to replace traditional fan cooling systems in pump motors. By measuring radiated noises, head, efficiency, and cavitation performance, the research compared the differences among experimental results of the original pump unit, the one with a normal design jetting pipe and another one with a larger jetting pipe. Results show that the radiated sound pressure level of the model pump was significantly reduced by 8.3 dB after integrating the jetting pipe. With a normal jetting pipe, no significant changes were observed in the head, efficiency, and shaft power curves, and cavitation performance improved under small flow rate. However, the performance with the larger jetting pipe worsened, except the hump phenomenon of the model pump under a small flow rate was enhanced. Computational fluid dynamics method was used to calculate the internal flow of three model pumps in order to investigate the jetting flow effect. A comparison among the flow fields at the inlet of the three types of pumps indicated that high-pressure water injection can effectively control inlet recirculation and improve velocity distribution in the inlet flow field with decreased recirculation vortex strength and recirculation onset critical flow rate.

“…[1][2][3][4][5][6] Due to the complicated distribution and variation of the multiphase flow in the cavitating pump, the transient characteristics of cavitation phenomenon should be investigated. Most existing papers of mixed-flow pump cavitation performance are studied by steady simulation method.…”

Section: Introductionmentioning

confidence: 99%

Pressure fluctuation and flow pattern of a mixed-flow pump with different blade tip clearances under cavitation condition

Tan

Liu

et al. 2017

Self Cite

Cavitation phenomenon has strong transient characteristics and is highly influenced by geometric structure. In this study, the cavitation performance with influence of blade tip clearance for a mixed-flow pump is studied using the renormalization group (RNG) k-e turbulence model and the Zwart-Gerber-Belamri cavitation model. The dominant frequency and maximum amplitude values at non-cavitation condition and different cavitation conditions are compared and associated with flow field features. The results show that the dominant frequency value under incipient cavitation and critical cavitation is 3.2f i and when the cavitation is severe, the frequency value changes to 3.5f i . Then, the influence of tip clearance width on cavitation performance of the mixed-flow pump is also discussed. The results show that the increase in tip clearance will significantly aggravate the performance drop of the pump under cavitation conditions. The critical net positive suction head value increases in 4.79% of the value under no-tip clearance condition. At the same time, by the inner flow field observation and analysis, the morphological of cavitation bubbles is also changed, and the cavitation bubbles tend to attach to the blade suction side and the attachment length increases as the tip clearance increases.