Study on improvement of hydraulic performance and internal flow pattern of the axial flow pump by groove flow control technology

To study the effect of sediment on the cavitation in the axial-flow pump, the method of CFD is employed to experiment on the internal flow field of the pump in the case of cavitation in clean water and sandy water separately. The calculation is done with different particle sizes and sediment concentrations. The results show that as the sediment concentration increases, the vortex range and cavitation area of the blade will further increase, and the flow pattern in the impeller becomes more disordered. The mechanism of action of particle size on cavitation is similar to that of sediment concentration. However, cavitation in clean water is quite different from that in sandy water in that the cavitation value and range in sandy water are significantly larger than that in clean water. By contrast, the particle size has little effect on the cavitation value and range. It proves that particle size does not have a great influence on cavitation distribution, but sediment concentration is the main factor affecting the cavitation performance of the pump. Moreover, sediment will disrupt the internal flow pattern of the pump, promote the development of cavitation and further reduce the cavitation performance of the pump.

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Fish-friendly design of an axial flow pump impeller based on a blade strike model

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1177/0957650919849768 ◽

2019 ◽

Vol 234 (2) ◽

pp. 173-186 ◽

Cited By ~ 1

Author(s):

Qiang Pan ◽

Weidong Shi ◽

Desheng Zhang ◽

BPM van Esch ◽

Ruijie Zhao

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Flow Behavior ◽

Integrated Design ◽

Axial Flow ◽

Hydraulic Performance ◽

Fish Mortality ◽

Computational Fluid Dynamics Analysis ◽

Axial Flow Pump ◽

Flow Pump

With environmental awareness growing in many countries, governments are taking measures to reduce mortality of migrating fish in pumping stations. Manufacturers seek to develop pumps that are less damaging to fish and still provide good hydraulic performance, but little is known about the implications design modifications may have on internal flow characteristics and overall hydraulic performance. In this paper, an integrated design method is proposed that combines a validated blade strike model for fish damage and a computational fluid dynamics method to assess the pump performance. A redesign of an existing, conventional, axial flow pump is presented as an example in this paper. It shows how the design of the impeller blades was modified stepwise in order to reduce fish mortality while its hydraulic performance was monitored. Computational fluid dynamics analysis of the flow near the hub of the highly skewed blades indicated that unconventional design modifications were required to ensure optimum flow behavior. In the final fish-friendly design, the risk of fish mortality has reduced considerably while the hydraulic performance of the pump is still acceptable for practical application.

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Interrelationship Between the Efficiency Characteristics and the Pressure Head Gradients Among Axial Flow Pumps

Volume 2: Design, Construction, and Operation Innovations; Compression and Pump Technology; SCADA, Automation, and Measurement; System Simulation; Geotechnical and Environmental ◽

10.1115/ipc1996-1892 ◽

1996 ◽

Author(s):

Takaharu Tanaka

Keyword(s):

Cross Section ◽

Flow Rate ◽

Axial Flow ◽

Internal Flow ◽

Pressure Head ◽

Design Flow ◽

Discharge Valve ◽

Head Gradient ◽

Axial Flow Pump ◽

Flow Pump

There is a correlation between the efficiency of the pump to the head produced. On the axial flow pump, whose efficiency characteristic is favorable, the pressure head gradient between the impeller inlet and the outlet sections, at an equivalent flow rate, may become larger than that for the less favorable axial flow pump. This fundamental interrelation may be held in the flow passage regardless to the flow rate whichever they are operated at design or off design flow rate. There may be a direct correlation between the efficiency of an axial flow pump and the ratio of the discharge valve cross section divided by the pipeline cross section. The smaller this ratio is the better the pressure head gradient is for the same flow rates. This ratio may be useful to estimate relative grade of heads, pressure head gradients, internal flow conditions, and efficiency characteristics among axial flow pumps.

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Improvement of the Efficiency of the Axial-Flow Pump at Part Loads due to Installing Outlet Guide Vanes Mechanism

Mathematical Problems in Engineering ◽

10.1155/2016/6375314 ◽

2016 ◽

Vol 2016 ◽

pp. 1-10 ◽

Cited By ~ 2

Author(s):

Fan Yang ◽

Hao-ru Zhao ◽

Chao Liu

Keyword(s):

Prediction Model ◽

Flow Rate ◽

High Efficiency ◽

Guide Vane ◽

Axial Flow ◽

Hydraulic Performance ◽

Operating Conditions ◽

Ann Model ◽

Axial Flow Pump ◽

Flow Pump

In order to investigate the influence of adjustable outlet guide vane on the hydraulic performance of axial-flow pump at part loads, the axial-flow pump with 7 different outlet guide vane adjustable angles was simulated based on the RNG k-ε turbulent model and Reynolds time-averaged equations. The Vector graphs of airfoil flow were analyzed in the different operating conditions for different adjustable angles of guide vane. BP-ANN prediction model was established about the effect of adjustable outlet guide vane on the hydraulic performance of axial-flow pump based on the numerical results. The effectiveness of prediction model was verified by theoretical analysis and numerical simulation. The results show that, with the adjustable angle of guide vane increasing along clockwise, the high efficiency area moves to the large flow rate direction; otherwise, that moves to the small flow rate direction. The internal flow field of guide vane is improved by adjusting angle, and the flow separation of tail and guide vane inlet ledge are decreased or eliminated, so that the hydraulic efficiency of pumping system will be improved. The prediction accuracy of BP-ANN model is 1%, which can meet the requirement of practical engineering.

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Numerical simulation on hydraulic performance and tip leakage vortex of a slanted axial-flow pump with different blade angles

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/09544062211032989 ◽

2021 ◽

pp. 095440622110329

Author(s):

Zhaodan Fei ◽

Hui Xu ◽

Rui Zhang ◽

Yuan Zheng ◽

Tong Mu ◽

...

Keyword(s):

Kinetic Energy ◽

Strain Tensor ◽

Axial Flow ◽

Hydraulic Performance ◽

Tip Leakage Flow ◽

Blade Angle ◽

Tip Leakage Vortex ◽

Tip Leakage ◽

Axial Flow Pump ◽

Flow Pump

The blade angle has a great effect on hydraulic performance and internal flow field for axial-flow pumps. This research investigated the effect of the blade angle on hydraulic performance and tip leakage vortex (TLV) of a slanted axial-flow pump. The hydraulic performance and the TLV are compared with different setting angles. The dimensionless turbulence kinetic energy (TKE) is used to investigate the TLV. A novel variable fv is utilized to analyze the relation among the TLV, strain tensor and vorticity tensor. The proper orthogonal decomposition (POD) method is used to analyze TLV structure. The results show that with the increase of the blade angle, the pump head is getting larger, the flow rate of the best efficiency moves to be larger, and both the primary TLV (P-TLV) and the secondary TLV (S-TLV) are getting stronger. The P-TLV often exists in the outer edge of TKE distribution and S-TLVs often exist in the largest value area of TKE. This phenomenon is more evident with blade angle increasing. Through POD method, it shows that the first six modes contain more than 90% of TKE. The reason why the TKE value near the region of S-TLV is high is that the tip leakage flow is a kind of jet-like flow with high kinetic energy. The main structure of the P-TLV is shown in modes 4−6, resulting in a reflux zone but not with the highest TKE.

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