Study on the Reduction of Pressure Fluctuation for a Double-Suction Centrifugal Pump With Staggered Blades

2018 ◽  
Author(s):  
Qian-qian Li ◽  
Da-zhuan Wu
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Cfd Simulation ◽  
Stokes Equations ◽  
Low Noise ◽  
Living Environment ◽  
Centrifugal Impeller ◽  
Fluctuation Analysis ◽  
Centrifugal Pumps ◽  
Vibration Performance

Due to the distinctive characteristic of massive flow rates, double-suction centrifugal pump has been extensively applied in lots of perspectives, such as drainage, irrigation, transportation projects and other hydraulic engineering realms. Nevertheless, the significance of the pressure fluctuation inside the double-suction centrifugal pump, which is getting more and more prominent under the soaring demands for low noise and comfortable living environment, could not be underestimated. Consequently, how to reduce the pressure fluctuation as far as possible and enhance the running stability of the pump is always the research hotspot. In this study, the double-suction centrifugal impeller with abominable vibration performance is redesigned to improve the internal flow and reduce the flow-induced noise. What’s addition, the two redesigned impellers wearing splitter blades were compared in staggered arrangement with different angles for the purpose of ulteriorly decreasing the pressure fluctuation. On the basis of Realizable k-ε model and SIMPLEC algorithm, the unsteady Reynolds-averaged Navier-Stokes equations (URANS) were resolved by means of CFD simulation and the flow performance and the vibration performance were validated with the experiments. The results illustrate that the redesigned impeller with multi-blade could raise the hydraulic performance and reduce the pressure fluctuation inside the pump. When the impeller of each side was laid with the staggered angle of 12 degrees, the pressure distribution tended to be more uniform and the pressure fluctuation was well ameliorated. Through the pressure fluctuation analysis in time domain and frequency domain, the pressure change inside the pumps could be evaluated quantitatively and accurately, hence different pumps could be contrasted in detail. The consequences of this paper could provide reference for pressure fluctuation reduction and vibration performance reinforcement of double-suction centrifugal pumps as well as other vane pumps.

scholarly journals Investigation on Reduction of Pressure Fluctuation for a Double-Suction Centrifugal Pump

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Qianqian Li ◽  
Shiyang Li ◽  
Peng Wu ◽  
Bin Huang ◽  
Dazhuan Wu
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
Fluctuation Analysis ◽  
Centrifugal Pumps ◽  
Large Power ◽  
Pressure Contour ◽  
Dimensionless Pressure ◽  
Fluctuation Amplitude ◽  
Radial Gap

AbstractDouble-suction centrifugal pumps have been applied extensively in many areas, and the significance of pressure fluctuations inside these pumps with large power is becoming increasingly important. In this study, a double-suction centrifugal pump with a high-demand for vibration and noise was redesigned by increasing the flow uniformity at the impeller discharge, implemented by combinations of more than two parameters. First, increasing the number of the impeller blades was intended to enhance the bounding effect that the blades imposed on the fluid. Subsequently, increasing the radial gap between the impeller and volute was applied to reduce the rotor-stator interaction. Finally, the staggered arrangement was optimized to weaken the efficacy of the interference superposition. Based on numerical simulation, the steady and unsteady characteristics of the pump models were calculated. From the fluctuation analysis in the frequency domain, the dimensionless pressure fluctuation amplitude at the blade passing frequency and its harmonics, located on the monitoring points in the redesigned pumps (both with larger radial gap), are reduced a lot. Further, in the volute of the model with new impellers staggered at 12°, the average value for the dimensionless pressure fluctuation amplitude decreases to 6% of that in prototype pump. The dimensionless root-mean-square pressure contour on the mid-span of the impeller tends to be more uniform in the redesigned models (both with larger radial gap); similarly, the pressure contour on the mid-section of the volute presents good uniformity in these models, which in turn demonstrating a reduction in the pressure fluctuation intensity. The results reveal the mechanism of pressure fluctuation reduction in a double-suction centrifugal pump, and the results of this study could provide a reference for pressure fluctuation reduction and vibration performance reinforcement of double-suction centrifugal pumps and other pumps.

CFD Simulation and Design Improvement of Internal Rotating Flow of Turbomachine

2020 ◽  
Author(s):  
Naseer Hadi ◽  
Badih Jawad ◽  
Munther Hermez ◽  
Hossam Metwally ◽  
Liping Liu
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
High Speed ◽  
Cfd Simulation ◽  
Stokes Equations ◽  
Normal Operation ◽  
Working Fluid ◽  
Centrifugal Impeller ◽  
Rotating Flow ◽  
Pump Performance

Abstract Designing a turbomachine comes with many challenges due to many parameters affecting its performance. This study presents a design to reduce losses in turbulence flow and surface friction by using a disk located between the rotating centrifugal impeller and the pump casing, which in turn enhances the centrifugal pump performance, upon rotating freely during normal operation. Under a constant operating speed of 3000 RPM, the new design is shown to improve the centrifugal pump performance. The turbulent flow between the rotating impeller and pump stationary walls increases the frictional losses. The highest friction occurs in the flow between two surfaces, one being close to zero velocity and the other one moving at high speed. Flow recirculation in the enclosure is a major problem that leads to a decrease in turbomachine’s performance. Two-dimensional Computational Fluid Dynamics (CFD) analysis is used to numerically simulate the rotating flow field inside the centrifugal pump chamber and to provide critical hydraulic design information. In this study, ANSYS-FLUENT R19.2 is used to analyze the input torque under different angular velocities by applying a disk with various thicknesses at four different locations to get the best results. The flow field in the chamber is investigated using 2-D Naiver-Stokes Equations with a Realizable k-ϵ turbulence model. Standard water was used as the working fluid. The numerical analysis gives an idea of how the freely rotating disks behave, and the results will be compared to find the most efficient case of centrifugal pump operation with an adjacent disk. The best-case new design will identify the highest reduction of input power by 24.4%. This study will introduce to the future work of a three-dimensional model.

Numerical Procedure for Assessment of Centrifugal Pump Cavitation Erosion

2008 ◽  
Author(s):  
Sergey F. Timushev ◽  
Vladimir A. Knyazev ◽  
Sergey S. Panaiotti ◽  
Vladimir A. Soldatov ◽  
Upendra Singh Rohatgi
Keyword(s):  
Centrifugal Pump ◽  
Cavitation Erosion ◽  
Stokes Equations ◽  
Splitting Method ◽  
Numerical Procedure ◽  
Cfd Modeling ◽  
Centrifugal Impeller ◽  
Uniform Pressure ◽  
Centrifugal Pumps ◽  
Erosion Damage

Currently the cavitation erosion damage becomes a critical issue that limits the centrifugal pump life cycle extension. Despite of a long history of studying the cavitation erosion phenomenon in centrifugal pumps there are still no reliable assessment methods except semi-empirical formula having rather limited application and accuracy. The paper is presenting a novel method for assessment of centrifugal pump cavitation erosion combining 3D unsteady flow CFD modeling and numerical analysis of cavitation bubbles behavior. The Navier-Stokes equations are solved by a splitting method with the implicit algorithm and high-order numerical scheme for convective transfer terms. The 3D numerical procedure is based on non-staggered Cartesian grid with adaptive local refinement and a sub-grid geometry resolution method for description of curvilinear complex boundaries like blade surfaces. Rotation is accounted with implementation of “sliding-grid” technology. The method considers evolution of the bubble in 3D flow from initial conditions until the disruption moment with determination of the erosion jet power impact. Validation of the method on model feed centrifugal pump stages is completed for two model centrifugal impellers Centrifugal impeller #1 is designed with a goal of through-passed shaft pump flow modeling. There are completed computations of cavitating bubbles’ evolution under non-uniform pressure field that show the non-uniform pressure distribution near the blade surface causes an essential influence on cavitation erosion. Computational prediction of the impeller #1 cavitation erosion damage is confirmed experimentally.

Experimental Investigation of Pressure Fluctuations on Inner Wall of a Centrifugal Pump

2019 ◽  
Vol 36 (4) ◽  
pp. 401-410 ◽  
Author(s):  
Xiao-Qi Jia ◽  
Bao-Ling Cui ◽  
Zu-Chao Zhu ◽  
Yu-Liang Zhang
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
High Flow ◽  
Low Flow ◽  
Centrifugal Pumps ◽  
Flow Rates ◽  
Pressure Distributions ◽  
Blade Passing Frequency

Abstract Affected by rotor–stator interaction and unstable inner flow, asymmetric pressure distributions and pressure fluctuations cannot be avoided in centrifugal pumps. To study the pressure distributions on volute and front casing walls, dynamic pressure tests are carried out on a centrifugal pump. Frequency spectrum analysis of pressure fluctuation is presented based on Fast Fourier transform and steady pressure distribution is obtained based on time-average method. The results show that amplitudes of pressure fluctuation and blade-passing frequency are sensitive to the flow rate. At low flow rates, high-pressure region and large pressure gradients near the volute tongue are observed, and the main factors contributing to the pressure fluctuation are fluctuations in blade-passing frequency and high-frequency fluctuations. By contrast, at high flow rates, fluctuations of rotating-frequency and low frequencies are the main contributors to pressure fluctuation. Moreover, at low flow rates, pressure near volute tongue increases rapidly at first and thereafter increases slowly, whereas at high flow rates, pressure decreases sharply. Asymmetries are observed in the pressure distributions on both volute and front casing walls. With increasing of flow rate, both asymmetries in the pressure distributions and magnitude of the pressure decrease.

scholarly journals Pressure Fluctuation Reduction of a Centrifugal Pump by Blade Trailing Edge Modification

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1408 ◽  
Author(s):  
Bin Huang ◽  
Guitao Zeng ◽  
Bo Qian ◽  
Peng Wu ◽  
Peili Shi ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Pressure Side ◽  
Centrifugal Pumps ◽  
Trailing Edge ◽  
Impeller Blade ◽  
Blade Passing Frequency ◽  
Impeller Outlet ◽  
Edge Profile ◽  
Edge Trimming

The pressure fluctuation inside centrifugal pumps is one of the main causes of hydro-induced vibration, especially at the blade-passing frequency and its harmonics. This paper investigates the feature of blade-passing frequency excitation in a low-specific-speed centrifugal pump in the perspective of local Euler head distribution based on CFD analysis. Meanwhile, the relation between local Euler head distribution and pressure fluctuation amplitude is observed and used to explain the mechanism of intensive pressure fluctuation. The impeller blade with ordinary trailing edge profile, which is the prototype impeller in this study, usually induces wake shedding near the impeller outlet, making the energy distribution less uniform. Because of this, the method of reducing pressure fluctuation by means of improving Euler head distribution uniformity by modifying the impeller blade trailing edge profile is proposed. The impeller blade trailing edges are trimmed in different scales, which are marked as model A, B, and C. As a result of trailing edge trimming, the impeller outlet angles at the pressure side of the prototype of model A, B, and C are 21, 18, 15, and 12 degrees, respectively. The differences in Euler head distribution and pressure fluctuation between the model impellers at nominal flow rate are investigated and analyzed. Experimental verification is also conducted to validate the CFD results. The results show that the blade trailing edge profiling on the pressure side can help reduce pressure fluctuation. The uniformity of Euler head circumferential distribution, which is directly related to the intensity of pressure fluctuation, is improved because the impeller blade outlet angle on the pressure side decreases and thus the velocity components are adjusted when the blade trailing edge profile is modified. The results of the investigation demonstrate that blade trailing edge profiling can be used in the vibration reduction of low specific impellers and in the engineering design of centrifugal pumps.

Influence of wall roughness on the static performance and pressure fluctuation characteristics of a double-suction centrifugal pump

2018 ◽  
Vol 232 (7) ◽  
pp. 826-840 ◽  
Author(s):  
Zhifeng Yao ◽  
Min Yang ◽  
Ruofu Xiao ◽  
Fujun Wang
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
Design Flow ◽  
Experimental Investigations ◽  
Wall Roughness ◽  
Detached Eddy Simulation ◽  
Centrifugal Pumps ◽  
Eddy Simulation ◽  
Static Performance

The unsteady flow field and pressure fluctuations in double-suction centrifugal pumps are greatly affected by the wall roughness of internal surfaces. To determine the wall roughness effect, numerical and experimental investigations were carried out. Three impeller schemes for different wall roughness were solved using detached eddy simulation, and the performance and pressure fluctuations resolved by detached eddy simulation were compared with the experimental data. The results show that the effects of wall roughness on the static performance of a pump are remarkable. The head and efficiency of the tested double-suction centrifugal pump are raised by 2.53% and 6.60% respectively as the wall roughness is reduced by means of sand blasting and coating treatments. The detached eddy simulation method has been proven to be accurate for the prediction of the head and efficiency of the double-suction centrifugal pump with roughness effects. The influence of the roughness on pressure fluctuation is greatly dependent on the location relative to the volute tongue region. For locations close to the volute tongue, the peak-to-peak value of the pressure fluctuations of a wall roughness of Ra = 0.10 mm may be 23.27% larger than the case where Ra = 0.02 mm at design flow rate.

scholarly journals Optimization and Analysis of Centrifugal Pump considering Fluid-Structure Interaction

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yu Zhang ◽  
Sanbao Hu ◽  
Yunqing Zhang ◽  
Liping Chen
Keyword(s):  
Centrifugal Pump ◽  
Fluid Structure Interaction ◽  
Kriging Model ◽  
Geometrical Parameters ◽  
Centrifugal Pumps ◽  
Transient Vibration ◽  
Pump Impeller ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Vibration Performance

This paper presents the optimization of vibrations of centrifugal pump considering fluid-structure interaction (FSI). A set of centrifugal pumps with various blade shapes were studied using FSI method, in order to investigate the transient vibration performance. The Kriging model, based on the results of the FSI simulations, was established to approximate the relationship between the geometrical parameters of pump impeller and the root mean square (RMS) values of the displacement response at the pump bearing block. Hence, multi-island genetic algorithm (MIGA) has been implemented to minimize the RMS value of the impeller displacement. A prototype of centrifugal pump has been manufactured and an experimental validation of the optimization results has been carried out. The comparison among results of Kriging surrogate model, FSI simulation, and experimental test showed a good consistency of the three approaches. Finally, the transient mechanical behavior of pump impeller has been investigated using FSI method based on the optimized geometry parameters of pump impeller.

The effect of wear ring clearance on flow field in the impeller sidewall gap and efficiency of a low specific speed centrifugal pump

2017 ◽  
Vol 232 (17) ◽  
pp. 3062-3073 ◽  
Author(s):  
M DaqiqShirazi ◽  
R Torabi ◽  
A Riasi ◽  
SA Nourbakhsh
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Volumetric Efficiency ◽  
Centrifugal Pumps ◽  
Disk Friction ◽  
Low Specific Speed ◽  
Overall Efficiency ◽  
Specific Speed

In this paper, the flow in the impeller sidewall gap of a low specific speed centrifugal pump is analyzed to study the effect of wear ring clearance and the resultant through-flow on flow field in this cavity and investigate the overall efficiency of the pump. Centrifugal pumps are commonly subject to a reduction in the flow rate and volumetric efficiency due to abrasive liquids or working conditions, since the wear rings are progressively worn, the internal leakage flow is increased. In the new operating point, the overall efficiency of the pump cannot be predicted simply by using the pump characteristic curves. The flow field is simulated with the use of computational fluid dynamics and the three-dimensional full Navier–Stokes equations are solved using CFX software. In order to verify the numerical simulations, static pressure field in volute casing and pump performance curves are compared with the experimental measurements. The results show that, for the pump with minimum wear ring clearance, the disk friction efficiency is the strongest factor that impairs the overall efficiency. Therefore, when the ring clearance is enlarged more than three times, although volumetric efficiency decreases effectively but the reduction in overall efficiency is remarkably smaller due to improvement in the disk friction losses.

Numerical Simulation of Cavitation Phenomena in a Centrifugal Pump

2009 ◽  
Author(s):  
Freddy Jeanty ◽  
Jesu´s De Andrade ◽  
Miguel Asuaje ◽  
Frank Kenyery ◽  
Auristela Va´squez ◽  
...  
Keyword(s):  
Experimental Data ◽  
Centrifugal Pump ◽  
Cfd Simulation ◽  
Common Phenomenon ◽  
Performance Parameters ◽  
Centrifugal Pumps ◽  
Cavitation Model ◽  
Cfd Simulations ◽  
Global Performance ◽  
Good Agreement

Cavitation is a common phenomenon that appears during the operation of the hydraulic turbomachines reducing performance and life of Centrifugal pumps. The main goal of this work is primarily a CFD-simulation of the whole Centrifugal Pump-Turbine including the suction cone, impeller, diffuser blades and volute, in order to characterize and evaluate its performance under cavitation conditions. The CFD simulations results were compared with experimental data under cavitation and non-cavitation conditions. A good agreement has been obtained under non-cavitation conditions for global performance parameters. After the implementation of the Rayleigh Plesset cavitation model, the required Net Positive Suction Head (NPSHr) has been predicted from CFD simulations. Finally, a full cavitation test can be reproduced for a Hydraulic Turbomachine to avoid this dangerous phenomenon.

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