scholarly journals CFD-Rotordynamics Sequential Coupling Simulation Approach for the Flow-Induced Vibration of Rotor System in Centrifugal Pump

2020 ◽  
Vol 10 (3) ◽  
pp. 1186
Author(s):  
Hehui Zhang ◽  
Haolin You ◽  
Haishan Lu ◽  
Kun Li ◽  
Zhiyong Zhang ◽  
...  
Keyword(s):  
Numerical Calculation ◽  
Centrifugal Pump ◽  
Dominant Frequency ◽  
Calculation Model ◽  
Rotor System ◽  
Centrifugal Pumps ◽  
Unstable Flow ◽  
Flow Induced Vibration ◽  
Sequential Coupling ◽  
Rotor Stator Interaction

Vibration of the rotor system is closely related with the operation stability of centrifugal pump, and it is inevitably induced by the unsteady inner flow. An unsteady computational fluid dynamics model coupling with a rotordynamics model was presented, and the corresponding numerical calculation program, including a self-designed rotordynamics code, was developed on the commercial package ANSYS Workbench. The validity of the numerical calculation model was verified by a hydraulic performance and vibration test based on an industrial centrifugal pump. The hydraulic radial forces on impeller, pressure pulsation, deformation, and vibration of the main shaft under nine different flow rates were systematically investigated and explained preliminarily from the view of inner unstable flow. Results show that the blade passing frequency is the dominant frequency in the fluctuation of the above dynamical behaviors, which is closely related to the rotor–stator interaction between the impeller and volute casing. This study built the connection between internal fluid flow in the centrifugal pump and the vibration of its external rotor structure, and may provide theoretical references for the design of vibration-reducing and safety monitoring strategies design of centrifugal pumps.

Effect of Blade Trailing Edge Cutting Angle on Unstable Flow and Vibration in a Centrifugal Pump

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Baoling Cui ◽  
Wenqing Li ◽  
Chenliang Zhang
Keyword(s):  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Low Frequency ◽  
Dominant Frequency ◽  
Design Flow ◽  
Centrifugal Pumps ◽  
Transient Pressure ◽  
Unstable Flow ◽  
Trailing Edge ◽  
Vibration Displacement

Abstract The vibration induced by the unsteady fluid exciting force in a centrifugal pump is one of the important factors affecting the reliable operation of the pump. In this study, the cutting of the blade trailing edge of a straight blade is presented to improve the unstable flow and vibration in a centrifugal pump. Based on the large eddy simulation (LES) and fluid–solid coupling method, the transient pressure pulsation, unstable flow structure, and vibration displacement of a centrifugal pump were investigated with different cutting angles of the trailing edge under the design flow rate. The external characteristics of the centrifugal pumps were calculated and compared using the shear stress transport (SST) k–ω turbulence model. The results show that the heads and efficiencies of the pumps with 30 deg and 45 deg cutting angles of the trailing edge slightly improved. The pressure pulsation on the volute evaluated by dominant frequency–amplitude and pressure pulsation energy was reduced due to the lesser average vorticity intensity and trailing vortex area in the centrifugal pump. Therefore, the vibration displacement and the vibration energy at the low frequency of the impeller decreased.

Design Optimization of Splitter Blade Impeller in a Centrifugal Pump

2020 ◽  
Author(s):  
Shunya Takao ◽  
Kentarou Hayashi ◽  
Masahiro Miyabe
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Design Method ◽  
General Purpose ◽  
Stable Operation ◽  
Centrifugal Pumps ◽  
Unstable Flow ◽  
Rate Range ◽  
Flow Rate Range ◽  
Suction Performance

Abstract In order to improve suction performance, centrifugal pumps with an inducer are used for rocket pumps, liquid gas transport such as LNG, and general-purpose pumps. Since a higher suction performance than conventional pump is required, a splitter blade that consists of a long blade and a short blade is sometimes adopted. However, the design becomes more difficult due to the increased number of parameters. The stable operation over a wide flow rate range are required in the general-purpose pumps. Therefore it is necessary to design them so that unstable flow phenomena such as surges do not occur. However, the design method to avoid them is not well understood yet. In this study, we focused on the splitter blade impeller in a general-purpose low-speed centrifugal pump with an inducer. Six parameters such as leading edge position and trailing edge position of the short blade for both hub-side and tip-side were set as design ones. A multi-objective optimization method using a commercial software was applied to improve suction performance while maintaining high efficiency. Then obtained optimal shape were analyzed by CFD calculation and extracted the feature. Furthermore, optimized impellers were manufactured and confirmed the performance over a wide flow rate range by experiments. In addition, a optimizing design method that improves pump performance at lower cost was studied.

Comparison of Inlet Curved Disk Arrangements for Suppression of Recirculation in Centrifugal Pump Impellers

2016 ◽  
Author(s):  
Munther Y. Hermez ◽  
Badih A. Jawad ◽  
Liping Liu ◽  
Vernon Fernandez ◽  
Kingman Yee ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
High Speed ◽  
Operating Cost ◽  
Three Dimensional ◽  
Centrifugal Pumps ◽  
Unstable Flow ◽  
Pump Impeller ◽  
Flow Rates ◽  
Flow Recirculation ◽  
Flow Field Characteristics

The present work aims to numerically study the inlet flow recirculation and modified impeller interaction in a centrifugal pump. An optimization of modified shrouded impeller with curved disk arrangement to suppress the unsteady flow recirculation is pursued. This modification will enhance the impeller characteristics with a wider operation range at both low and high flow rates in a high speed centrifugal pump type. The unstable flow in the centrifugal pumps is a common problem that leads to damage in the pump’s internal parts, consequently increases the operating cost. At certain flow rates, generally below the Best Efficiency Point (BEP), all centrifugal pumps are subject to internal recirculation occurs at the suction and discharge areas of the impeller. For decades, experimental work has been done to investigate the complex three-dimensional flow within centrifugal pumps impellers, before computational work gains momentum due to advancement of computing power and improved numerical codes. In this study the impeller with a curved disk arrangement has been investigated by using a three-dimensional Navier-Stokes code with a standard k-ε turbulence model. The purpose is to evaluate and select the optimum impeller modification that would increase the pump suction flow rate range. Three-dimensional numerical Computational Fluid Dynamics (CFD) tools are used to simulate flow field characteristics inside the centrifugal pump and provide critical hydraulic design information. In the present work, ANSYS v.16.1 Fluent solver is used to analyze the pressure and velocity distributions inside impeller suction and discharge passages. The ultimate goal of this study is to manufacture and validate the most optimized and efficient centrifugal pump impeller with a curved disk. The best case curve identifies the highest increase of total pressure difference by 22.1%, and highest efficiency by 92.3% at low flowrates.

Effects of Centrifugal Pumps Outlet Angle on Flow Induced Vibration and Noise

2012 ◽  
Vol 249-250 ◽  
pp. 460-465 ◽  
Author(s):  
Yong Wang ◽  
Jian Wang ◽  
Dong Xi Liu ◽  
Hou Lin Liu
Keyword(s):  
Centrifugal Pump ◽  
Virtual Instrument ◽  
Noise Signal ◽  
Centrifugal Pumps ◽  
Flow Induced Vibration ◽  
Vibration Intensity ◽  
Minimum Value ◽  
Outlet Angle ◽  
Frequency Peak ◽  
Impeller Outlet

In order to research the effects of impeller outlet angles on flow induced vibration and noise of centrifugal pumps, a single grade end suction centrifugal pump is employed as a research object. The outlet angles were varied from 33° to 29°and 37°, but the volute and the other geometric parameters keep constant. Based on the virtual instrument data acquisition system, pump product testing system and in the centrifugal pump closed experimental rig, the flow induced vibration and noise signals of model pump with different outlet angles in the full flow range are measured and analyzed. Experimental results show that the influence of flow induced vibration on volute is the largest. With the increase of impeller outlet angle, the variation tendency of vibration intensity for 4 measure points decrease. The vibration intensity of model pump gets the minimum value, when the outlet angle is 37°. Under different conditions, the shaft frequency peak of noise signal varied intricately with the increase of impeller outlet angle. When the outlet angle is 33°, the shaft frequency peak of the model pump is relatively small under each operating condition, and gets the minimum value at the design condition.

Influence of Impeller Sinusoidal Tubercle Trailing Edge On Pressure Pulsation in a Centrifugal Pump At Nominal Flow Rate

2021 ◽  
Author(s):  
Yanpi Lin ◽  
Xiaojun Li ◽  
Bowen Li ◽  
Xiao-Qi Jia ◽  
Zuchao Zhu
Keyword(s):  
Centrifugal Pump ◽  
High Speed ◽  
Pressure Pulsation ◽  
Humpback Whales ◽  
Centrifugal Pumps ◽  
Trailing Edge ◽  
Rotor Stator Interaction ◽  
High Speed Rotation ◽  
Operation Stability ◽  
Speed Rotation

Abstract The high-speed rotation of impellers leads to strong rotor-stator interaction, which mainly causes the pressure pulsation of centrifugal pumps. An impeller with a bionic sinusoidal tubercle trailing edge (STTE) can reduce the intensity of the rotor-stator interaction and thus reduce the pressure pulsation of the centrifugal pump. In this study three profiles of STTE were designed based on the pectoral fin structure of humpback whales of which the influence on the pressure pulsation of centrifugal pumps was studied via experiment and numerical simulation. Results show that a reasonable design of STTE can effectively eliminate the high-frequency pressure pulsation in the rotor-stator interaction region of the centrifugal pump. The use of STTE2 and STTE3 profiles affects the amplitude reduction of pressure pulsation at the blade passing frequency (fBPF). Compared with the impeller without the STTE profile, the amplitudes of pressure pulsation with STTE2 and STTE3 profiles are decreased by 47.10% and 44.20% at the pump discharge, while the decrease, at the volute throat are 30.36% and 25.97%, respectively. Detailed flow structures inside the pump show that the STTE profile can inhibit the vortex generation at the blade trailing edge, and the local high-intensity pressure pulsation can be reasonably avoided. This study helps improve the pressure pulsation characteristic of centrifugal pumps and their operation stability.

scholarly journals Numerical Investigation of Pressure Fluctuation Characteristics in a Centrifugal Pump with Variable Axial Clearance

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Lei Cao ◽  
Zhengwei Wang ◽  
Yexiang Xiao ◽  
Yongyao Luo
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
Maximum Pressure ◽  
Centrifugal Pumps ◽  
Pressure Surface ◽  
Clearance Flow ◽  
Rotor Stator Interaction ◽  
Entire Flow ◽  
Axial Clearance

Clearance flows in the sidewall gaps of centrifugal pumps are unsteady as well as main flows in the volute casing and impeller, which may cause vibration and noise, and the corresponding pressure fluctuations are related to the axial clearance size. In this paper, unsteady numerical simulations were conducted to predict the unsteady flows within the entire flow passage of a centrifugal pump operating in the design condition. Pressure fluctuation characteristics in the volute casing, impeller, and sidewall gaps were investigated with three axial clearance sizes. Results show that an axial clearance variation affects the pressure fluctuation characteristics in each flow domain by different degree. The greatest pressure fluctuation occurs at the blade pressure surface and is almost not influenced by the axial clearance variation which has a certainly effect on the pressure fluctuation characteristics around the tongue. The maximum pressure fluctuation amplitude in the sidewall gaps is larger than that in the volute casing, and different spectrum characteristics show up in the three models due to the interaction between the clearance flow and the main flow as well as the rotor-stator interaction. Therefore, clearance flow should be taken into consideration in the hydraulic design of centrifugal pumps.

Experimental Investigation on Unsteady Pressure Pulsation in a Centrifugal Pump With Special Slope Volute

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Ning Zhang ◽  
MinGuan Yang ◽  
Bo Gao ◽  
Zhong Li ◽  
Dan Ni
Keyword(s):  
Experimental Investigation ◽  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
High Amplitude ◽  
Operating Conditions ◽  
Stable Operation ◽  
Flow Induced Vibration ◽  
Unsteady Pressure ◽  
Rotor Stator Interaction ◽  
Nonlinear Components

Rotor–stator interaction, a major source of high amplitude pressure pulsation and flow-induced vibration in the centrifugal pump, is detrimental to stable operation of pumps. In the present study, a slope volute is investigated to explore an effective method to reduce high pressure pulsation level, and its influence on flow structures is analyzed using numerical simulation. The stress is placed on experimental investigation of unsteady pressure pulsation inside the slope volute pump. For that purpose, pressure pulsations are extracted at nine locations along the slope volute casing covering sensitive pump regions. Results show that distinct pressure pulsation peaks at fBPF, together with nonlinear components are captured. These peaks are closely related to the position of pressure transducer and operating conditions of the pump. The improvement of rotational speed of the impeller results in rapid increase of pressure fluctuation amplitude at fBPF and corresponding root mean square (RMS) value within 10–500 Hz. A comparison with conventional spiral volute pump is implemented as well, and it is demonstrated that slope volute contributes significantly to the decline of pressure pulsation level.

Influence of Geometry of Inlet Guide Vanes on Pressure Fluctuations of a Centrifugal Pump

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Ming Liu ◽  
Lei Tan ◽  
Shuliang Cao
Keyword(s):  
Centrifugal Pump ◽  
Turbulence Model ◽  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Maximum Amplitude ◽  
Dominant Frequency ◽  
Centrifugal Pumps ◽  
Maximum Increase ◽  
Guide Vanes ◽  
Inlet Guide Vanes

Prewhirl regulation by inlet guide vanes (IGVs) has been proven as an effective method for operation regulation of centrifugal pumps. By contrast, the influence of the geometry of IGVs on operation stability of centrifugal pump remains unknown. The pressure fluctuations and flow patterns in a centrifugal pump without and with two-dimensional (2D) or three-dimensional (3D) IGVs are investigated numerically at 1.0Qd, 0.6Qd, and 1.2Qd. Renormalization group (RNG) k–ε turbulence model is used as turbulence model, and fast Fourier transform (FFT) method is used to analyze the pressure fluctuations. The dominant frequency of pressure fluctuations in impellers is either the rotational frequency fi or twice thereof for pumps without and with IGVs at three flow rates, while the dominant frequency is constantly the blade passing frequency in volute. For 1.0Qd, the comparison of pumps without IGVs indicates that the maximum amplitude of pressure fluctuations at fi in pumps with 2D IGVs is decreased by an average of 22.2%, and the amplitude is decreased by an average of 44.9% in pumps with 3D IGVs. The IGVs mainly influence the pressure fluctuations at fi but indicate minimal influence at 2fi. For 0.6Qd, the comparison of pumps without IGVs denotes that the maximum amplitudes of pressure fluctuations at fi in pumps with 2D or 3D IGVs both increase; the maximum increase is 2.01%. For 1.2Qd, the comparison of pumps without IGVs indicates that the maximum amplitudes of pressure fluctuations at fi in pumps with 2D or 3D IGVs both decrease; the maximum decline is 15.9%.

Numerical Determination of the Acoustic Impedance of a Centrifugal Pump

2011 ◽  
Author(s):  
Rau´l Barrio ◽  
Eduardo Blanco ◽  
Jens Keller ◽  
Jorge Parrondo ◽  
Joaqui´n Ferna´ndez
Keyword(s):  
Centrifugal Pump ◽  
Acoustic Impedance ◽  
Close Relation ◽  
Centrifugal Pumps ◽  
Total Load ◽  
Outlet Port ◽  
Acoustic Coupling ◽  
Rotor Stator Interaction ◽  
Hydraulic Network ◽  
D Model

The perturbations generated at the blade-passing frequency and higher harmonics in centrifugal pumps due to the rotor-stator interaction represent a significant contribution to the total load on the machine, which can bring about excessive vibration and noise levels thus limiting the pump performance. These perturbations are in close relation to the pump’s internal geometry and also to the point of operation; in addition, their magnitude is influenced by the acoustic coupling between the pump and the pipelines. The latter can be characterized by the equivalent acoustic impedance; however, the acoustic characterization of the pump is more complex. The usual boundary conditions imposed in numerical simulations of centrifugal pumps (constant outlet velocity, constant static pressure, or pressure loss proportional to squared velocity) induce a particular type of coupling between the pump and the hydraulic network. Hence, the real performance values of the pump are expected to change from those obtained in the simulations if the coupling conditions are modified. The purpose of the present investigation is to obtain a simple 1-D model for the acoustic impedance of a volute-type centrifugal pump from the full 3-D unsteady flow simulations carried out with the code Fluent®. For this purpose, a specific pressure fluctuation is imposed at the outlet port of the pump by means of a user-defined function. The amplitude and frequency of this fluctuation is modified to obtain the response of the pump (i.e., the acoustic impedance) for a series of flow rates. The acoustic 1-D model obtained will allow a quick prediction of the perturbations generated from the acoustic impedance of the network to which the pump is to be coupled.

Effect of semi-open impeller side clearance on centrifugal pump cavitation inception

2018 ◽  
Vol 1 (2) ◽  
pp. 24-39
Author(s):  
A. Farid ◽  
A. Abou El-Azm Aly ◽  
H. Abdallah
Keyword(s):  
Centrifugal Pump ◽  
Static Pressure ◽  
Rotation Speed ◽  
Centrifugal Pumps ◽  
Severe Condition ◽  
Cavitation Inception ◽  
Total Input ◽  
Input Pressure ◽  
Pump Head ◽  
Pump Pressure

Cavitation in pumps is the most severe condition that centrifugal pumps can work in and is leading to a loss in their performance.  Herein, the effect of semi-open centrifugal pump side clearance on the inception of pump cavitation has been investigated.  The input pump pressure has been changed from 80 to 16 kPa and the pump side clearance has been changed from 1 mm to 3 mm at a rotation speed of 1500 rpm. It has been shown that as the total input pressure decreased; the static pressure inside the impeller is reduced while the total pressure in streamwise direction has been reduced, also the pump head is constant with the reduction of the total input pressure until the cavitation is reached. Head is reduced due to cavitation inception; the head is reduced in the case of a closed impeller with a percent of 1.5% while it is reduced with a percent of 0.5% for pump side clearance of 1mm, both are at a pressure of 20 kPa.   Results also showed that the cavitation inception in the pump had been affected and delayed with the increase of the pump side clearance; the cavitation has been noticed to occur at approximate pressures of 20 kPa for side clearance of 1mm, 18 kPa for side clearances of 2mm and 16 kPa for 3mm.

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