scholarly journals Experiment and simulation about the effect of wear-ring abrasion on the performance of a marine centrifugal pump

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199811
Author(s):  
Wu Xianfang ◽  
Du Xinlai ◽  
Tan Minggao ◽  
Liu Houlin
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Vibration Velocity ◽  
Test Results ◽  
Obvious Effect ◽  
Performance Change ◽  
Pump Test ◽  
Simulation Results ◽  
Axis Passing

The wear-ring abrasion can cause performance degradation of the marine centrifugal pump. In order to study the effect of front and back wear-ring clearance on a pump, test and numerical simulation were used to investigate the performance change of a pump. The test results show that the head and efficiency of pump decrease by 3.56% and 9.62% respectively at 1.0 Qd due to the wear-ring abrasion. Under 1.0 Qd, with the increase of the front wear-ring the vibration velocity at pump foot increases from 0.4 mm/s to 1.0 mm/s. The axis passing frequency (APF) at the measuring points increases significantly and there appears new characteristic frequency of 3APF and 4APF. The numerical simulation results show that the front wear-ring abrasion affects the flow at the inlet of the front chamber of the pump and impeller passage. And the back wear-ring abrasion has obvious effect on the flow in the back chamber of the pump and impeller passage, while the multi-malfunction of the front wear-ring abrasion and back wear-ring abrasion has the most obvious effect on the flow velocity and flow stability inside pump. The pressure pulsation at Blade Passing Frequency (BPF) of the three schemes all decrease with the increase of the clearance.

Numerical Simulation of the Kinetic Energy Projectile Oblique Penetration into the Concrete

2014 ◽  
Vol 989-994 ◽  
pp. 982-985
Author(s):  
Jun Chen ◽  
Xiao Jun Ye
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Kinetic Energy ◽  
Three Dimensional ◽  
Test Results ◽  
Destruction Process ◽  
3D Finite Element ◽  
Finite Element Software ◽  
Simulation Results ◽  
Target Characteristics

ANSYS-LS/DYNA 3D finite element software projectile penetrating concrete target three-dimensional numerical simulation , has been the target characteristics and destroy ballistic missile trajectory , velocity and acceleration and analyze penetration and the time between relationship , compared with the test results , the phenomenon is consistent with the simulation results. The results show that : the destruction process finite element software can better demonstrate concrete tests revealed the phenomenon can not be observed , estimated penetration depth and direction of the oblique penetration missile deflection .

scholarly journals Experimental Research and Numerical Simulation on Grouting Quality of Shield Tunnel Based on Impact Echo Method

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Fei Yao ◽  
Guangyu Chen ◽  
Jianhong Su
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Working Conditions ◽  
Acoustic Impedance ◽  
Shield Tunnel ◽  
Test Results ◽  
Impact Echo ◽  
Simulation Results ◽  
The Impact ◽  
Impact Echo Method

To identify shield grouting quality based on impact echo method, an impact echo test of segment-grouting (SG) test piece was carried out to explore effect of acoustic impedance of grouting layers and grouting defects on impact echo law. A finite element numerical simulation on the impact echo process was implemented. Test results and simulation results were compared. Results demonstrated that, under some working conditions, finite element simulation results and test results both agree with theoretical values. The acoustic impedance ratio of SG material influenced the echo characteristics significantly. But thickness frequency could not be detected under some working conditions because the reflected energy is weak. Frequency feature under grouting defects was more complicated than that under no grouting defects.

Numerical study on instantaneous radial force of a centrifugal pump for different working conditions

2019 ◽  
Vol 37 (2) ◽  
pp. 458-480
Author(s):  
Xiaoqi Jia ◽  
Sheng Yuan ◽  
Zuchao Zhu ◽  
Baoling Cui
Keyword(s):  
Numerical Simulation ◽  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Working Conditions ◽  
Flow Rate ◽  
Pressure Pulsation ◽  
Radial Force ◽  
Leakage Rate ◽  
Content Type ◽  
Three Components

Purpose Instantaneous radial force induced from unsteady flow will intensify vibration noise of the centrifugal pump, especially under off-design working conditions, which will affect safety reliability of pump operation in severe cases. This paper aims to conduct unsteady numerical computation on one centrifugal pump; thus, unsteady fluid radial force upon the impeller and volute is obtained, so as to study the evolution law of instantaneous radial force, the internal relationship between radial force and pressure pulsation, the relationship among each composition of radial force that the impeller received and the influence of leakage rate of front and back chamber on radial force. Design/methodology/approach The unsteady numerical simulation with SST k-ω turbulence model was carried out for a low specific-speed centrifugal pump using computational fluid dynamics codes FLUENT. The performance tests and pressure tests were conducted by a closed loop system. The performance curves and the pressure distribution from numerical simulation agree with that of the experiment conducted. The unsteady pressure distributions and the instantaneous radial forces induced from unsteady flow were analyzed under different flow rates. Contribution degrees of three components of the radial force on the impeller and the relation between the radial force and leakage rate were analyzed. Findings Radial force on the volute and pressure pulsation on the volute wall have the same distribution tendency, but in contrast to the distribution trend of the radial force on the impeller. In the component of radial force that the impeller received, radial force on the blade accounts for the main position. With the decrease of flow rate, ratio of the radial force on front and back casings will be increased; under large flow rate, vortex and flow blockage at volute section will enhance the pressure and radial force fluctuation greatly, and the pulsation degree may be much more intense than that of a smaller flow rate. Originality/value This paper revealed the relation of the radial force and the pressure pulsation. Meanwhile, contribution degrees of three components of the radial force on the impeller under different working conditions as well as the relation between the radial force and leakage rate of front and rear chambers were analyzed.

Numerical Seakeeping Simulation of Model Test Condition for Two-Ship Interaction in Waves

2007 ◽  
Author(s):  
Lin Li
Keyword(s):  
Numerical Simulation ◽  
Model Test ◽  
Current Paper ◽  
Free Motion ◽  
Test Results ◽  
Wave Excitation ◽  
Motion Constraints ◽  
Test Conditions ◽  
Motion Modes ◽  
Simulation Results

In order to validate the numerical prediction of two-ship interactions in waves, the model test calibration has to be conducted. However, motion constraints are usually applied when model tests are carried out for the measurement of wave excitation forces and moments in certain selected motion modes for both ships. Therefore, in current paper, a numerical seakeeping simulation of the model test conditions has been studied. Restraints in surge, sway and yaw, as well as the free motion modes in heave, roll and pitch have been all applied to both the ships, experimentally and numerically. The restraint forces and the unrestrained motions have been compared with the model test results and numerical simulation results. Fairly good agreements have been found.

Numerical Simulation of the Transient Flow in a Pump-Turbine During the Load Rejection Process With Special Emphasis on the Cavitation Effect

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Xiaolong Fu ◽  
Deyou Li ◽  
Hongjie Wang ◽  
Guanghui Zhang ◽  
Zhenggui Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Single Phase ◽  
Pressure Pulsation ◽  
Phase Flow ◽  
Cavitation Flow ◽  
Single Phase Flow ◽  
Pump Turbine ◽  
Cavitation Effect ◽  
Simulation Results ◽  
Load Rejection Process

Abstract At present, pumped-storage power technology is the only available and effective way for the load balancing and energy storage in the grid network scale. During the frequent switch back and forth conditions, there are severe pressure pulsation and cavitation in pump-turbines. However, their generation mechanism has not been determined yet. This work contributes to the numerical simulation of the transient behaviors in a prototype pump-turbine during the load rejection process with special emphasis on cavitation effect. In this study, the two-dimensional dynamic remesh and variable speed slide mesh methodologies were employed to perform the simulation of the transient single-phase flow and cavitation flow in a pump-turbine. The simulation results of single-phase flow and cavitation flow were both consistent with the experimental data except in local regions based on the experimental validation of prototype tests. However, the numerical results considering cavitation effects have a better behavior than those of single-phase flow in the predictions of pressure pulsation and rotational speed. Then, the cavitation flow simulation results were analyzed deeply, especially in pressure pulsation and cavitation flow field. Analysis revealed that three typical complex frequency components of pressure were captured in the cavitation flow, which significantly affect the axial hydraulic thrust on the runner. And it is validated that they are primarily induced by the cavity collapse near the trailing edges of the runner blades in reverse pump mode and the interaction between cavitation and vortex rope in draft-tube in turbine mode.

Computer Simulation of a Transportation Package Impacting Concrete and Soil Targets

2004 ◽  
Author(s):  
S. N. Huang ◽  
S. S. Shiraga ◽  
L. M. Hay
Keyword(s):  
Numerical Simulation ◽  
Computer Simulation ◽  
Impact Test ◽  
Impact Behavior ◽  
Test Results ◽  
Hypothetical Accident ◽  
Simulation Results ◽  
Accident Conditions ◽  
The Impact

This paper compares transportation mockup cask impact test results onto real surfaces with FEA numerical simulation results. The impact test results are from a series of cask impact tests that were conducted by Sandia National Laboratories (Gonzales 1987). The Sandia tests were conducted with a half-scale instrumented cask mockup impacting an essentially unyielding surface, in-situ soil, concrete runways, and concrete highways. The cask numerical simulations with these same surfaces are conducted with ABAQUS/Explicit, Version 5.8, The results are then compared and evaluated to access the viability of using numerical simulation to predict the impact behavior of transportation casks under hypothetical accident conditions.

Study on the Porous Media Used in Numerical Simulation of Temperature Characteristic for Isothermal Chambers

2011 ◽  
Vol 291-294 ◽  
pp. 1689-1692
Author(s):  
Li Hong Yang ◽  
Da Hua Liu
Keyword(s):  
Numerical Simulation ◽  
Porous Medium ◽  
Porous Media ◽  
Flow Rate ◽  
Temperature Characteristic ◽  
Test Results ◽  
Temperature Characteristics ◽  
Simulation And Experiment ◽  
Simulation Results ◽  
Metal Wires

Isothermal chamber, which is fabricated by empty chamber stuffed with thin metal wires, is a kind of test devices for flow rate characteristics of pneumatic components, and its temperature characteristics are critical to the accuracy of test results. In this paper, the stuffers in isothermal chamber were considered as porous medium with large porosity, so the temperature characteristics could be studied by numerical simulation. Though there are differences between simulation and experiment, they have same trends and the law of variation can be seen from the simulation results, which demonstrates the reliability of numerical simulation. Consequently, simulation can be an efficient method, which is energy-saving and cost-reducing.

Numerical Simulation of Temperature Effect of Concrete Hydration

2008 ◽  
Vol 400-402 ◽  
pp. 483-488 ◽  
Author(s):  
Lu Wang ◽  
Ying Min Li ◽  
Li Ping Liu ◽  
Shang Ling Xue ◽  
Xun Dai ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Temperature Effect ◽  
Temperature Stress ◽  
Superposition Principle ◽  
Material Behavior ◽  
Test Results ◽  
Heat Generation Rate ◽  
Scaled Model ◽  
Concrete Hydration ◽  
Simulation Results

Based on the improved equation of concrete heat-generation rate and an improved calculation method of temperature stress, the temperature effect of concrete hydration heat is simulated successfully in ANSYS. Comparison between the numerical simulation results and test results of a scaled model of blast furnace foundation indicates that the calculated temperature field based on the improved equation and method is much closer to that of test than which obtained by the old equation and method. By using the stress superposition principle, the temperature-stress field can be calculated with considering the change of material behavior with temperature and time.

Experimental and Numerical Simulation on the Starting Period of a Centrifugal Pump

2008 ◽  
Author(s):  
Gang Chen ◽  
Jie Shao ◽  
Yulin Wu ◽  
Guangjun Cao
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Close Relation ◽  
Significant Advance ◽  
Rotating Speed ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Pump Test ◽  
Startup Period ◽  
Data Acquiring

The centrifugal pump is applied widely in many fields with significant advance made in the understanding of the key technical phenomena related to its running at constant rotating speed; and more and more studies are concerned about its transient operation, because its design not only has close relation with operation parameters under constant speed but also those under the startup and shutoff period, especial the pressure fluctuation and hydraulic performance. In order to investigate the transient characteristics during the startup period of a centrifugal pump, the experiment is carried out and numerical simulation is made. The experiment was conducted on the POL’s pump test rig, and the rapid data acquiring program was added in order to get the torque, pressure, and rotating speed during the startup period. Based on the torque equations induced in the paper, numerical simulation is made with the Large Eddy Simulation (LES) method and UDFs (User Defined Functions). Comparison of pump heads and rotating speed between simulation and experimental results shows that they are in good agreement, indicating that the dynamic characteristics of the centrifugal pump can be predicted accurate comparatively through simulation with LES method during its startup process. In addition, the pressure distribution of half height of vane on the cross section at different time was obtained, showing that the pressure increases with time going.

Experimental Study on a New Suction Inlet Realizable for Uniform Thickness Collection

2011 ◽  
Vol 308-310 ◽  
pp. 1609-1613
Author(s):  
Si Lin Chen ◽  
Xu Dong Yang ◽  
Shi Qiu ◽  
Chun Lin Ma ◽  
Tao Chen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Rake Angle ◽  
External Flow ◽  
Test Results ◽  
Uniform Thickness ◽  
Bulk Materials ◽  
Work Surface ◽  
Simulation Results ◽  
Calculation Software

The numerical simulation of flow field of a new rectangular suction inlet installing guide plates with different rake angles was carried out by means of the K-ε turbulence model based on the Fluent hydromechanics calculation software. And that the influences of different rake angles of the internal guide plates on the flow field were analyzed. Consequently, the optimal rake angle of 45° was defined at last. Finally, the practical rectangle suction inlet, according to the numerical simulation results, was developed by installing internal guide plates with the optimal rake angle, which optimizes the distribution of internal and external flow field and improves the average side velocities of flow. Practical test results indicate that the new rectangular suction inlet could realize the uniform thickness collection to achieve the smooth work surface when collecting the bulk materials.

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