scholarly journals The mechanism of joint effects of axial-flow pump cavitation and sediment wear

2020 ◽  
Vol 12 (5) ◽  
pp. 168781402092306
Author(s):  
Peng Lin ◽  
Dong Hu ◽  
Zi-jun Lin ◽  
Mei-qing Liu ◽  
Chuan-lin Tang ◽  
...  
Keyword(s):  
Particle Size ◽  
Wear Rate ◽  
Volume Fraction ◽  
Axial Flow ◽  
Sediment Concentration ◽  
Sediment Distribution ◽  
Joint Effects ◽  
Multiple Variables ◽  
Axial Flow Pump ◽  
Flow Pump

This article studies the flow trajectories and the wear law of sediment particles in a pump considering multiple variables, such as sediment concentration, particle size, and cavitation stage. In addition, the mechanism of joint effects of cavitation and sediment wear of the axial-flow pump is explored. In this work, the characteristics of cavitation and sediment wear in an axial-flow pump are investigated by the numerical simulation using shear stress transport k–ω turbulence model with experimental validation. The external characteristics of experimental results and numerical simulations are in agreement. The results show that the sediment concentration exerts a profound influence on the vacuole distribution in the pump, while the particle size has little effect on it. Cavitation can increase the volume fraction of the solid, accelerate the wear on the components, and affect the sediment distribution in the impeller. Cavitation and sediment wear are mutually worsening, and their joint effects will form a vicious circle. With the decrease in inlet pressure and the increase in sediment concentration and particle size, the maximum wear rate will gradually increase, which proves that cavitation, sediment concentration, and particle size are the main factors that influence the maximum wear rate.

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.

Analysis of Solid-Liquid Two-Phase Flow in Axial Flow Pump

2012 ◽  
Vol 229-231 ◽  
pp. 559-564
Author(s):  
Hong Hua ◽  
Xiao Lin Wang ◽  
Hui Yan Wang ◽  
Xiao Bing Liu
Keyword(s):  
Axial Flow ◽  
Sediment Concentration ◽  
Secondary Development ◽  
Turbulent Model ◽  
Two Phase ◽  
Simplec Algorithm ◽  
Axial Flow Pump ◽  
Pump Inlet ◽  
Solid Liquid ◽  
Flow Pump

The liquid-solid two-phase turbulent flow in an axial flow pump was numerically simulated by using the SIMPLEC algorithm based Navier-Stoker and RNG k-ε turbulent model and after the secondary development of the software Fluent. The distributions of solid concentration, velocity and pressure on the impellers of the axial flow pump were analyzed at different volume concentrations at the pump inlet. The numerical results show that the head and the efficiency of the pump will reduce with the increasing of the sediment concentration in sandy rivers. This research shows that the numerical simulation results are consistent with the actual situations.

scholarly journals Numerical simulation and optimization of solid-liquid two-phase flow in a back-swept axial-flow pump

2017 ◽  
Vol 21 (4) ◽  
pp. 1751-1757 ◽  
Author(s):  
De-Sheng Zhang ◽  
Qiang Pan ◽  
Zhang Hu ◽  
Wei-Dong Shi ◽  
Rui-Jie Zhang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Sewage Treatment Plant ◽  
Particle Diameter ◽  
Axial Flow ◽  
Wear Property ◽  
Simulation And Optimization ◽  
Axial Flow Pump ◽  
Flow Pump

The simulation study is proposed to analyze the wear property of the axial flow pump using the sewage as medium. Different axial flow pumps are designed with different back-swept angles, of which are 40?, 65?, and 90?. Numerical simulation results showed the relationship between solid volume fraction and back-swept angle on the pressure/suction surface, as well as the particle diameter. To validate the correctness of numerical investigation, the result of the 65? backswept blade model was compared with a sludge axial flow pump in sewage treatment plant, which showed fair agreement with the simulated results.

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.

Performance evaluation of an axial-flow pump with adjustable guide vanes in turbine mode

2016 ◽  
Vol 99 ◽  
pp. 1146-1152 ◽  
Author(s):  
Zhongdong Qian ◽  
Fan Wang ◽  
Zhiwei Guo ◽  
Jie Lu
Keyword(s):  
Performance Evaluation ◽  
Axial Flow ◽  
Guide Vanes ◽  
Axial Flow Pump ◽  
Turbine Mode ◽  
Flow Pump

The Effect of the Thickness and Angle of the Inlet and Outlet Guide Vane on the Performance of Axial-Flow Pump

2016 ◽  
Author(s):  
Sang-Won Kim ◽  
Youn-Jea Kim
Keyword(s):  
Numerical Analysis ◽  
Numerical Study ◽  
Guide Vane ◽  
Axial Flow ◽  
Inlet Guide Vane ◽  
Guide Vanes ◽  
Pump Performance ◽  
Blade Thickness ◽  
Axial Flow Pump ◽  
Flow Pump

An axial-flow pump has a relatively high discharge flow rate and specific speed at a relatively low head and it consists of an inlet guide vane, impeller, and outlet guide vane. The interaction of the flow through the inlet guide vane, impeller, and outlet guide vane of the axial-flow pump has a significant effect on its performance. Of those components, the guide vanes especially can improve the head and efficiency of the pump by transforming the kinetic energy of the rotating flow, which has a tangential velocity component, into pressure energy. Accordingly, the geometric configurations of the guide vanes such as blade thickness and angle are crucial design factors for determining the performance of the axial-flow pump. As the reliability of Computational Fluid Dynamics (CFD) has been elevated together with the advance in computer technology, numerical analysis using CFD has recently become an alternative to empirical experiment due to its high reliability to measure the flow field. Thus, in this study, 1,200mm axial-flow pump having an inlet guide vane and impeller with 4 blades and an outlet guide vane with 6 blades was numerically investigated. Numerical study was conducted using the commercial CFD code, ANSYS CFX ver. 16.1, in order to elucidate the effect of the thickness and angle of the guide vanes on the performance of 1,200mm axial-flow pump. The stage condition, which averages the fluxes between interfaces and is accordingly appropriate for the evaluation of pump performance, was adopted as the interface condition between the guide vanes and the impeller. The rotational periodicity condition was used in order to enable a simplified geometry to be used since the guide vanes feature multiple identical regions. The shear stress transport (SST) k-ω model, predicting the turbulence within the flow in good agreement, was also employed in the CFD calculation. With regard to the numerical simulation results, the characteristics of the pressure distribution were discussed in detail. The pump performance, which will determine how well an axial-flow pump will work in terms of its efficiency and head, was also discussed in detail, leading to the conclusion on the optimal blade thickness and angle for the improvement of the performance. In addition, the total pressure loss coefficient was considered in order to investigate the loss within the flow paths depending on the thickness and angle variations. The results presented in this study may give guidelines to the numerical analysis of the axial-flow pump and the investigation of the performance for further optimal design of the axial-flow pump.

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.

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