scholarly journals Internal Flow and Limiting Streamlines Observations of Contra-Rotating Axial Flow Pump at Partial Flow Rate

2011 ◽  
Vol 4 (2) ◽  
pp. 235-242 ◽  
Author(s):  
Satoshi Watanabe ◽  
Shimpei Momosaki ◽  
Satoshi Usami ◽  
Akinori Furukawa
Keyword(s):  
Flow Rate ◽  
Axial Flow ◽  
Internal Flow ◽  
Axial Flow Pump ◽  
Limiting Streamlines ◽  
Flow Pump

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

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.

1713 The Internal Flow of Contra-rotating Axial Flow Pump at Partial Flow Rate

2008 ◽  
Vol 2008.2 (0) ◽  
pp. 67-68
Author(s):  
Yusuke TSUNENARI ◽  
Akinori FURUKAWA ◽  
Satoshi WATANABE ◽  
Kusuo OKUMA ◽  
Satoshi USAMI
Keyword(s):  
Flow Rate ◽  
Axial Flow ◽  
Internal Flow ◽  
Axial Flow Pump ◽  
Flow Pump

Internal Flow Mechanism of Axial-Flow Pump With Adjustable Guide Vanes

2013 ◽  
Author(s):  
Honggeng Zhu ◽  
Rentian Zhang ◽  
Bin Xi ◽  
Dapeng Hu
Keyword(s):  
Flow Rate ◽  
Axial Flow ◽  
Internal Flow ◽  
Flow Angle ◽  
Guide Vanes ◽  
Setting Angle ◽  
Pumping Efficiency ◽  
Outlet Flow ◽  
Axial Flow Pump ◽  
Flow Pump

Axial-flow pumps are widely used in many fields where low pumping head and large flow rate are required such as irrigation and drainage, flood control, bio-environmental protection and inter-basin water diversion. Conventional axial-flow pump diffuser is designed with post fixed guide vanes to eliminate circulation, diffuse water and decrease flow velocity while converting dynamic energy to pressure energy. Under designed flow rate the inlet setting angle of the fixed guide vanes is designed to be equal to the outlet flow angle of the impeller blades which is regarded to be the best operating condition. Under off-design conditions the outlet flow angle of the impeller blades does not match the inlet setting angle of guide vanes any more. As a result hydraulic losses are increased, flow separation appeared and vortex generated inside the diffuser, the operation conditions of pump is deteriorated, bringing in bad cavitation characteristics, more energy consumption and lower pumping efficiency. The proposal of Axial-flow pumps with adjustable guide vanes are put forward in this paper, in which the inlet setting angle of guide vanes can be adjusted to coordinate with the change of flow rate and impeller blade setting angle and guarantee the outlet flow angle of impeller blades matching the inlet setting angle of guide vanes. The three-dimensional time-averaged N-S equations, closed by the standard κ–ε turbulence model, are adopted to simulate the internal flow fields of axial-flow pumps with fixed and adjustable guide vanes, and their performances are predicted. The internal flow mechanism of an axial-flow pump with adjustable guide vanes is investigated, and computational fluid dynamics is adopted to simulate and analyze the internal flow fields. Computation results indicate that the value of the highest pumping efficiency is slight changed while the vane setting angle is adjusted when the inlet setting angles of blades are fixed and the setting angles of guide vanes are regulated. Under off-design conditions the flow conditions inside the diffuser of axial-flow pump with adjustable guide vanes can be improved, the hydraulic loss reduced and the pumping efficiency can be raised effectively.

Flow Measurement at Partial Flow Rate With LDV Around Rear Rotor of Contra-Rotating Axial Flow Pump

2007 ◽  
Author(s):  
Shuichi Yamashita ◽  
Satoshi Watanabe ◽  
Kusuo Okuma ◽  
Kyota Shirasawa ◽  
Akinori Furukawa
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Flow Measurement ◽  
Axial Flow ◽  
Internal Flow ◽  
Stable Operation ◽  
Pressure Measurements ◽  
Specific Speed ◽  
Axial Flow Pump ◽  
Flow Pump

An application of contra-rotating rotors, in which a rear rotor is employed in tandem with a front one and these rotors rotate in the opposite direction each other, has been proposed against a demand for developing higher specific speed axial flow pump. The internal flow field of pump should be considered in the design for higher performance and more stable operation. The flow field in contra-rotating axial flow pump was measured with LDV and wall pressure measurements. In the present paper, the experimental results are shown and the flow behaviors would be discussed.

Numerical and Experimental Investigation of Tip Leakage Vortex Trajectory in an Axial Flow Pump

2013 ◽  
Author(s):  
Desheng Zhang ◽  
Weidong Shi ◽  
Suqing Wu ◽  
Dazhi Pan ◽  
Peipei Shao ◽  
...  
Keyword(s):  
Flow Rate ◽  
Axial Flow ◽  
Tip Clearance ◽  
High Speed Photography ◽  
Rate Condition ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Starting Point ◽  
Axial Flow Pump ◽  
Flow Pump

In this paper, the tip leakage vortex (TLV) structures in an axial flow pump were investigated by numerical and experimental methods. Based on the comparisons of different blade tip clearance size (i.e., 0.5 mm, 1mm and 1.5mm) and different flow rate conditions, TLV trajectories were obtained by Swirling Strength method, and simulated by modified SST k-ω turbulence model with refined high-quality structured grids. A high-speed photography test was carried out to capture the tip leakage vortex cavitation in an axial flow pump with transparent casing. Numerical results were compared with the experimental leakage vortex trajectories, and a good agreement is presented. The detailed trajectories show that the start point of tip leakage vortex appears near the leading edge at small flow rate, and it moves from trailing edge to about 30% chord span at rated flow rate. At the larger flow rate condition, the starting point of TLV shifts to the middle of chord, and the direction of TLV moves parallel to the blade hydrofoil. As the increasing of the tip size, the start point of TLV trajectories moves to the central of chord and the minimum pressure in vortex core is gradually reduced.

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

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
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.

scholarly journals Study on the Performance Improvement of Axial Flow Pump’s Saddle Zone by Using a Double Inlet Nozzle

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1493
Author(s):  
Weidong Cao ◽  
Wei Li
Keyword(s):  
Flow Rate ◽  
Three Dimensional ◽  
Axial Flow ◽  
Rotating Stall ◽  
Stable Operation ◽  
Inlet Section ◽  
Pump Impeller ◽  
Rate Condition ◽  
Axial Flow Pump ◽  
Flow Pump

The operating range of axial flow pumps is often constrained by the onset of rotating stall. An improved method using a double inlet nozzle to stabilize the performance curve is presented in the current study; a single inlet nozzle and three kinds of double inlet nozzle with different rib gap widths at the inlet of axial flow pump impeller were designed. Three dimensional (3D) incompressible flow fields were simulated, and the distributions of turbulence kinetic energy and velocity at different flow rates located at the inlet section, as well as the pressure and streamline in the impeller, were obtained at the same time. The single inlet nozzle scheme and a double inlet nozzle scheme were studied; the experimental and numerical performance results show that although the cross section is partly blocked in the double inlet nozzle, the head and efficiency do not decline at stable operation flow rate. On small flow rate condition, the double inlet nozzle scheme effectively stabilized the head-flow performance, whereby the block induced by the backflow before the impeller was markedly improved by using a double inlet nozzle. It has also been found that the rib gap width impacts the efficiency curve of the axial flow pump.

PIV Measurements and CFD Analysis in an Axial-Flow Pump

2007 ◽  
Author(s):  
Fang-Ping Tang ◽  
Chao Liu ◽  
Ji-Ren Zhou ◽  
Hua Yang ◽  
Li Cheng
Keyword(s):  
Flow Rate ◽  
Outer Part ◽  
Axial Flow ◽  
Operating Conditions ◽  
Design Flow ◽  
Separation Flow ◽  
Mean Velocity ◽  
Piv Measurements ◽  
Axial Flow Pump ◽  
Flow Pump

In this study, an axial flow pump impeller without guide vanes is experimentally investigated. The impeller used in the experiments consists of four blades. The particle image velocimetry technique and a five-hole probe have been used. Measurements of flow velocities in the outer part of the impeller have been made. PIV measurements have been realized in 12 meridian planes between blade-to-blade for design and off-design operating conditions. The meridian velocity is obtained with phase averaged method and the total circumferential mean velocity is obtained with an arithmetical average over the 12 circumferential data. The calculation is based on the CFX-TASC flow CFD code solving the three-dimensional Reynolds-averaged Navier-Stokes equation with RNG k–ε model of turbulence. The paper focuses on the comparisons of the results. Difference for the flow field between numerical and experimental results is small at large and design flow rate, while big difference occurs at small flow rate. It indicates that the numerical model is not suitable for separation flow.

scholarly journals CFD numerical simulation of sand-contained cavitation characteristics of axial-flow pump

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110327
Author(s):  
Peng Lin ◽  
Dong Hu ◽  
Jing-Man Lu ◽  
Shu Wang
Keyword(s):  
Particle Size ◽  
Flow Pattern ◽  
Great Influence ◽  
Axial Flow ◽  
Internal Flow ◽  
Sediment Concentration ◽  
Clean Water ◽  
Cavitation Performance ◽  
Axial Flow Pump ◽  
Flow Pump

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.

Sign in / Sign up

Export Citation Format

Share Document