Flow Characteristics of High-Efficient Axial Flow Pump System

2015 ◽  
Author(s):  
Chao Liu ◽  
Fan Yang ◽  
Yan Jin ◽  
Hua Yang
Keyword(s):  
Flow Characteristics ◽  
Axial Flow ◽  
Internal Flow ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Hydraulic Loss ◽  
Pump System ◽  
High Efficient ◽  
Axial Flow Pump ◽  
Flow Pump

Three-dimensional flow-fields in a high-efficient axial flow pump system were simulated by CFD to further study the internal flow characteristics. The internal flow patterns of the pump system were obtained at large, small and optimum operating conditions. The highest efficiency of pump system measured and calculated are 82.57% and 81% respectively at blade angle 0°. For the suction passage, the axial velocity distribution uniformity reach 97.51%, and the hydraulic loss is 0.039m, the pipe efficiency calculated is 98.5% at the optimum operating conditions. The maximum velocity is 1.429 m/s in the range of operating conditions, which meet the requirement of National standard. The performances predicted were compared with measurement results. It was found that the calculated results agree well with the measured results. The overall flow pattern of the pump system is uniform and smooth, and the hydraulic loss is very small which gives the excellent hydraulic performances of pump system.

An analysis on the flow characteristics of bi-directional axial-flow pump under reverse operation

2017 ◽  
Vol 231 (3) ◽  
pp. 239-249 ◽  
Author(s):  
Pengfei Ma ◽  
Jun Wang
Keyword(s):  
Flow Characteristics ◽  
Axial Flow ◽  
Internal Flow ◽  
Optimum Operating ◽  
Reverse Direction ◽  
Guide Vanes ◽  
Flow Loss ◽  
Axial Flow Pump ◽  
Object Of Study ◽  
Flow Pump

When the conventional bent guide vanes are applied to the bi-directional axial-flow pump, its performance declines considerably under reverse operation. Regarding a bi-directional axial-flow pump with high specific speed as the object of study, the variation of both hydraulic performance and internal flow field under reverse operation are analyzed in this paper. The results indicate that both the head and efficiency of the pump will drop greatly and the optimum operating point lean to the lower flow rate when it operates in the reverse direction, mainly due to the prewhirl caused by the guide vanes; the shedding vortex is formed after flow separation occurred near the trailing edge of blade, and its scale keeps increasing in the diffusing pipe during its motion until it collapses in the straight pipe, which is the major causes of the big flow loss and significant decline of the performance under reverse operation.

scholarly journals Numerical and Experimental Investigation of Internal Flow Characteristics and Pressure Fluctuation in Inlet Passage of Axial Flow Pump under Deflection Flow Conditions

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5245
Author(s):  
Fan Yang ◽  
Zhongbin Li ◽  
Yao Yuan ◽  
Chao Liu ◽  
Yiqi Zhang ◽  
...  
Keyword(s):  
Flow Characteristics ◽  
Axial Flow ◽  
Reliability And Validity ◽  
Internal Flow ◽  
Rotation Frequency ◽  
Hydraulic Loss ◽  
Flow Conditions ◽  
Monitoring Point ◽  
Axial Flow Pump ◽  
Flow Pump

The deflection flow of inlet passage seriously affects the performance of axial flow pump devices, and reduces the operation efficiency and stability of pumping station systems. In this paper, the influence of different deflection angles on the internal flow characteristics and outlet pulsation characteristics of the inlet passage of the vertical axial flow pump are studied. Based on the Reynolds time-averaged N-S equation of the three-dimensional incompressible fluid and the standard k-ε turbulence model, the model axial flow pump device was numerically simulated. Under optimal working conditions (Qbep = 31.04 L/s), the internal flow field of the axial flow pump was analyzed to study the change law of the axial flow pump performance under different deflection angles. Under the flow conditions of 0.6 Qbep, 1.0 Qbep and 1.2 Qbep, the pulsation characteristics of the outlet of inlet passage in axial flow pump at different deflection angles were analyzed. The result shows that with the increase of the deflection angle, the flow pattern of the inlet passage becomes turbulent, forming vortices of different sizes, the hydraulic loss of the inlet passage increases continuously, and the uniformity of the outlet flow velocity of the inlet passage increases first and then decreases. The time-domain waveform of outlet of the inlet passage at the pressure pulsation monitoring point has obvious periodicity, and the dominant frequency of the monitoring point is four times the rotation frequency, which corresponds to the number of impeller blades. It shows that the numerical calculation is in good agreement with the experimental results, which proves the reliability and validity of the numerical simulation calculation.

scholarly journals Effect of Tip Clearance on Helico-Axial Flow Pump Performance at Off-Design Case

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1653
Author(s):  
Nengqi Kan ◽  
Zongku Liu ◽  
Guangtai Shi ◽  
Xiaobing Liu
Keyword(s):  
Optimization Design ◽  
Flow Characteristics ◽  
Axial Flow ◽  
Leading Edge ◽  
Tip Clearance ◽  
Hydraulic Loss ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Axial Flow Pump ◽  
Flow Pump

To reveal the effect of tip clearance on the flow behaviors and pressurization performance of a helico-axial flow pump, the standard k-ε turbulence model is employed to simulate the flow characteristics in the self-developed helico-axial flow pump. The pressure, streamlines and turbulent kinetic energy in a helico-axial flow pump are analyzed. Results show that the tip leakage flow (TLF) forms a tip-separation vortex (TSV) when it enters the tip clearance and forms a tip-leakage vortex (TLV) when it leaves the tip clearance. As the blade tip clearance increases, the TLV moves along the blade from the leading edge (LE) to trailing edge (TE). At the same time, the entrainment between the TLV and the main flow deteriorates the flow pattern in the pump and causes great hydraulic loss. In addition, the existence of tip clearance also increases the possibility of TLV cavitation and has a great effect on the pressurization performance of the helico-axial flow pump. The research results provide the theoretical basis for the structural optimization design of the helico-axial flow pump.

Research on the Geometry Parameters of Diffuser Vane Influence on the Performance of Bulb Tubular Pumping System

2017 ◽  
Author(s):  
Yan Jin ◽  
Junxin Wu ◽  
Hongcheng Chen ◽  
Chao Liu
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Design Parameters ◽  
Hydraulic Loss ◽  
Three Dimensional Flow ◽  
Pump System ◽  
Pumping System ◽  
Axial Flow Pump ◽  
Cfd Method ◽  
Flow Pump

Diffuser vane of tubular pump is different with that of the axial flow pump, since the diffusion angle after the impeller is larger than as usual, which is an important part of bulb tubular pump system. By calculating the hydraulic loss of each part of bulb tubular pump system, it is found that the hydraulic loss of diffuser vane is in large proportion of the whole hydraulic loss. For this situation, focuses on the design parameters of diffuser vane such as diffuser vane length, unilateral edge diffusion angle, equivalent diffusion angle are necessary. In this paper, CFD method is used to simulate the turbulent flow in a bulb tubular pumping system with two different diffuser vanes. The three dimensional flow fields in the whole passage of pumping system with different diffuser vanes are obtained. The results show that all the main geometry parameters of the diffuser vane design affect the performances of tubular pumping system, it should be chosen the parameters reasonably based on the actual situation.

Numerical study on the internal flow characteristics of an axial-flow pump under stall conditions

2018 ◽  
Vol 32 (10) ◽  
pp. 4683-4695 ◽  
Author(s):  
Kan Kan ◽  
Yuan Zheng ◽  
Yujie Chen ◽  
Zhanshan Xie ◽  
Guang Yang ◽  
...  
Keyword(s):  
Numerical Study ◽  
Flow Characteristics ◽  
Axial Flow ◽  
Internal Flow ◽  
Axial Flow Pump ◽  
Flow Pump

Computer-Aided Design and Numerical Flow Analysis of Axial-Flow Pump With Inducer

2006 ◽  
Author(s):  
Yaojun Li ◽  
Fujun Wang
Keyword(s):  
Flow Characteristics ◽  
Axial Flow ◽  
Leading Edge ◽  
Hydraulic Loss ◽  
Trailing Edge ◽  
Impeller Blade ◽  
Pump Design ◽  
Axial Flow Pump ◽  
Flow Pump ◽  
Blade Leading Edge

Axial-flow pump equipped with inducer are widely used in marine propulsion systems. The interaction of inducer and impeller has significant effect on the performance of pump. In this study, a special axial-flow pump is designed and analysed by CAD-CFD approaches to study the interaction of inducer and impeller. The pump includes two main elements, an inducer with 3 blades mounted on a conical hub and a 6-blade impeller. The blade angle of impeller is adjustable to generate different relative circumferential angles between the inducer blade trailing edge and the impeller blade leading edge. The 3D pump solid model is generated by taking the data file as interface between hydraulic-design and 3D modelling. A computational fluid dynamics code is used to investigate the flow characteristics and performance of the axial-flow pump. Numerical simulation is performed by adopting 3D RANS equations with RNG k-epsilon turbulence model. An unstructured grid system and the finite-volume method are used for the solution procedure of the discretized governing equations for this problem. The rotator-stator interaction is treated with a multiple reference frame (MRF) strategy. Computations are performed in different cases: 7 different relative circumferential angles (Δθ) between the inducer blade trailing edge and the impeller blade leading edge, 3 different axial gaps (G) between the inducer and the impeller. Variation of the hydraulic loss in the rotator is obtained with the change of delta theta. The numerical results show that the pressure generated is minimum in case of (G = 3%D). This indicates that the interference between inducer and impeller is strong if the axial gap is small. The pump performances are predicted and compared to the experimental measurements. The current investigation leads to a thorough enough understanding of the flow characteristics in axial-flow pumps with complex configurations. Recommendations for future modifications and improvements to the pump design are also given.

scholarly journals Investigation into the Influence of Division Pier on the Internal Flow and Pulsation in the Outlet Conduit of an Axial-Flow Pump

2021 ◽  
Vol 11 (15) ◽  
pp. 6774
Author(s):  
Fan Yang ◽  
Dongjin Jiang ◽  
Tieli Wang ◽  
Pengcheng Chang ◽  
Chao Liu ◽  
...  
Keyword(s):  
Velocity Distribution ◽  
Pressure Pulsation ◽  
Axial Flow ◽  
Hydraulic Loss ◽  
Main Frequency ◽  
Starting Position ◽  
The Difference ◽  
Axial Flow Pump ◽  
Outlet Conduit ◽  
Flow Pump

The outlet conduit is an important construction connecting the outlet of the pump guide vane and the outlet pool; in order to study the hydraulic performance of the straight outlet conduit of the axial-flow pump device, this paper adopts the method of numerical simulation and analyzes the influence of the division pier on the pressure and velocity distribution inside and near the wall of the straight outlet conduit based on three design schemes. Four pressure pulsation measuring points were arranged in the straight outlet conduit, and the low-frequency pulsation characteristic information inside the straight outlet conduit with and without the division pier was extracted by wavelet packet reconstruction. The results show that the addition of a division pier has an effect on the hydraulic loss, near-wall pressure and velocity distribution in the straight outlet conduit. A small high-pressure zone is formed near the wall at the starting position of the division pier, and a large high-speed zone is formed on the left side at the starting position of the division pier. The length of the division pier has no significant effect on the flow distribution of the straight outlet conduit and the pressure and velocity distribution near the wall. Under different working conditions, each monitoring point has the maximum energy in the sub-band (0~31.25 Hz). With the increase of the flow rate, the total pressure energy of the straight outlet conduit decreases gradually. Under each condition, the difference of the energy proportion of the horizontal monitoring points of the straight outlet conduit is small, and the difference of the energy proportion of the two monitoring points at the top and bottom of the outlet channel is relatively large. The energy of the two monitoring points in the straight outlet conduit with a division pier is smaller than that of the two monitoring points in the straight outlet conduit without a division pier. There are differences in the main frequency and the power spectrum corresponding to the main frequency of the monitoring points in the straight outlet conduit, and the reasonable setting of the division pier is conducive to reducing the pressure pulsation of the flow in the straight outlet conduit and is beneficial to the safe and stable operation of the pump device.

Foetal bypass: concepts and controversies

Perfusion ◽  
1998 ◽  
Vol 13 (2) ◽  
pp. 111-117 ◽  
Author(s):  
Joseph J Sistino
Keyword(s):  
Heart Defects ◽  
Open Heart Surgery ◽  
Axial Flow ◽  
Right Atrial ◽  
Cyclooxygenase Inhibitors ◽  
Pump System ◽  
Maternal Risk ◽  
Valvular Stenosis ◽  
Axial Flow Pump ◽  
Flow Pump

One of the most controversial and challenging surgical undertakings of the next century promises to be foetal cardiac surgery. Animal studies have been underway for several years to gain an understanding of the physiological mechanisms required to achieve this undertaking. Not since the days of crosscirculation has there been a maternal risk associated with open-heart surgery. The diagnosis of congenital heart defects with foetal ultrasound can now be made as early as 12 weeks gestation. Simple cardiac abnormalities, such as valvular stenosis or atresia, alter intracardiac flow patterns and affect normal cardiac chamber development. Without early intervention, these complex lesions often require major surgical reconstruction, beginning in the neonatal period. Foetal cardiac bypass techniques have evolved from the use of roller pumps and bubble oxygenators primed with maternal blood to the use of an axial flow pump incorporated in a right atrial to pulmonary artery or aortic shunt. Because the blood entering the right atrium is oxygenated by the placenta, an oxygenator in the bypass circuit is probably not needed. The low prime axial flow pump system avoids the dilution of the foetus with the maternal adult haemoglobin and improves the outcome. A major focus of research has concentrated on maintenance of placental blood flow with the use of vasodilators and cyclooxygenase inhibitors. Investigation with primates will be necessary to confirm the placental physiology before human operations can be performed. As the foetal bypass challenges are overcome, there is the potential for a reduction in the number of complex cardiac lesions requiring early surgical intervention in the twenty-first century.

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.

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