Analysis of unsteady radial forces of multistage centrifugal pump with double volute

2018 ◽  
Vol 35 (3) ◽  
pp. 1500-1511 ◽  
Author(s):  
Baoling Cui ◽  
Xiaodi Li ◽  
Kun Rao ◽  
Xiaoqi Jia ◽  
Xiaolin Nie
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Static Pressure ◽  
Radial Force ◽  
Radial Vibration ◽  
Flow Rates ◽  
Content Type ◽  
Blade Passing Frequency ◽  
Multistage Centrifugal Pump ◽  
Radial Forces

Purpose Radial vibration of horizontal centrifugal pump has a close association with radial exciting forces. The purpose of this paper is to analyze the unsteady radial force in multistage centrifugal pump with double volute in detail and investigate the relevance of static pressure, radial force and radial vibration. Design/methodology/approach The unsteady numerical simulation with realizable k-ε turbulence model was carried out for a multistage centrifugal pump with double volute using computational fluid dynamics codes Fluent. The performance tests were conducted by use of a closed loop system and performance curves from numerical simulation agree with that of experiment. Vibration tests were carried out by vibration probes instrumented on the bearing cover of pump near no-driven end. Fast Fourier transform was used to obtain the frequency components of radial forces on the impellers from numerical simulation, which are compared with ones of radial vibration from experiment in Y and Z direction. And the static pressure distributions in the impeller were analyzed under different flow rates. Findings The symmetrical double volute can effectively balance radial forces. The maximum radial force and vibration velocity appear at 0.6 Q among the three flow rates 0.6 Q, Q and 1.2 Q. The frequencies corresponding to relatively large amplitude of vibration velocities and radial forces on the impellers in Y direction are blade passing frequency of the impellers. Blade passing frequency of first-stage impeller and shaft frequency are predominating in Z direction. It indicates that the radial vibration of centrifugal pump is closely related to the unsteady radial force. Originality/value The unsteady radial forces of the impeller in multistage centrifugal pump with double volute were comprehensively analyzed. The radial forces should be considered to balance during the design of multistage centrifugal pump.

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.

Hydrodynamic Design of the Volute of a Centrifugal Pump Using CFD

2011 ◽  
Author(s):  
Rouhollah Torabi ◽  
S. Ahmad Nourbakhsh
Keyword(s):  
Viscous Flow ◽  
Centrifugal Pump ◽  
Static Pressure ◽  
Design Method ◽  
Radial Force ◽  
Inverse Design ◽  
Radial Forces ◽  
Low Specific Speed ◽  
Specific Speed ◽  
Inverse Design Method

The objective of this paper is to develop the shape of an existing volute so that the radial forces in off-design condition become minimum. For this purpose 3-D inverse design method based on the 3-D viscous flow calculations was applied to re-design the geometry of the volute of a low specific speed pump. Various aspects of the geometry change independently to achieve the best one which produces less radial force in off design conditions. Measurements included time-averaged values of velocity and static pressure at a large number of locations in the volute.

Study on Radial Forces of Centrifugal Pumps With Various Collectors

2011 ◽  
Author(s):  
Zhongyong Pan ◽  
Junjie Li ◽  
Shuai Li ◽  
Shouqi Yuan
Keyword(s):  
Numerical Simulation ◽  
Pressure Distribution ◽  
Radial Force ◽  
Time Dependent ◽  
Centrifugal Pumps ◽  
Flow Rates ◽  
Trade Off ◽  
Blade Passage ◽  
Design Choice ◽  
Radial Forces

Numerical simulation is presented to study the steady and unsteady radial forces in a centrifugal pump with various collectors. The radial forces are obtained by integrating the pressure distribution around the impeller circumference. The calculated radial forces both time-dependent and independent at different flow rates caused by the collectors are compared. The results show that some conclusions do not consistent with the conventional experience as the collectors with double volute and vaned volute significantly decrease the radial forces and the radial force close a circle during the period of one blade passage passing. The combination of impeller and double volute is a trade-off design choice as it has significantly decreased the radial forces than that of single volute and its configuration is more compact than that of vaned collector.

Steady and Unsteady Radial Forces for a Centrifugal Pump With Impeller to Tongue Gap Variation

2005 ◽  
Vol 128 (3) ◽  
pp. 454-462 ◽  
Author(s):  
José González ◽  
Jorge Parrondo ◽  
Carlos Santolaria ◽  
Eduardo Blanco
Keyword(s):  
Centrifugal Pump ◽  
Numerical Results ◽  
Momentum Exchange ◽  
Unsteady Forces ◽  
Flow Rates ◽  
Pressure Distributions ◽  
Blade Passing Frequency ◽  
Wide Range ◽  
Radial Forces ◽  
Similarity Laws

Experimental and numerical studies are presented on the steady and unsteady radial forces produced in a single volute vaneless centrifugal pump. Experimentally, the unsteady pressure distributions were obtained using fast response pressure transducers. These measurements were compared with equivalent numerical results from a URANS calculation, using the commercial code FLUENT. Two impellers with different outlet diameters were tested for the same volute, with radial gaps between the blade and tongue of 10.0% and 15.8% of the impeller radius, for the bigger and smaller impeller diameters, respectively. Very often, pump manufacturers apply the similarity laws to this situation, but the measured specific speeds in this case were found to be slightly different. The steady radial forces for the two impellers were calculated from both the measured average pressure field and the model over a wide range of flow rates in order to fully characterize the pump behavior. Again, a deviation from the expected values applying the similarity laws was found. The data from the pressure fluctuation measurements were processed to obtain the dynamic forces at the blade passing frequency, also over a wide range of flow rates. Afterwards, these results were used to check the predictions from the numerical simulations. For some flow rates, the bigger diameter produced higher radial forces, but this was not to be a general rule for all the operating points. This paper describes the work carried out and summarizes the experimental and the numerical results, for both radial gaps. The steady and unsteady forces at the blade passing frequency were calculated by radial integration of the pressure distributions on the shroud side of the pump volute. For the unsteady forces, the numerical model allowed a separate analysis of the terms due to the pressure pulsations and terms related to the momentum exchange in the impeller. In this way, the whole operating range of the pump was studied and analyzed to account for the static and dynamic flow effects. The unsteady forces are very important when designing the pump shaft as they can produce a fatigue collapse if they are not kept under a proper working value.

scholarly journals Numerical Simulation Research on Radial Force of Centrifugal Pump with Guide Vanes

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Dongrong Meng ◽  
Ting Jiang ◽  
Hongling Deng ◽  
Gaoyang Hou
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Guide Vane ◽  
Radial Force ◽  
Flow State ◽  
Simulation Research ◽  
Flow Rates ◽  
Guide Vanes ◽  
Vector Distribution ◽  
Unsteady Numerical Simulation

To reveal the internal unsteady flow state of the guide vane centrifugal pump, in this paper, the standard SST k‐ω turbulent flow model is used for unsteady numerical simulation of the centrifugal pump. The characteristics of the flow field inside the centrifugal pump are analyzed, the resultant force and vector distribution of the radial force of the guide vane and impeller of the centrifugal pump under different flow rates are obtained, which were verified by experiments. The results show that the main reason of radial force of the impeller is the pressure asymmetry in each flow passage. The radial force will show periodic fluctuations due to the rotor-stator interference between the impeller and the guide vanes under different flow rates. The radial force on the impeller decreases gradually with the increase of the flow, the distribution is hexagonal or hexagonal shape, and the number of impeller blades is the same. The results can provide reference for the design of impeller and guide vane of centrifugal pump.

Unsteady Radial Forces on the Impeller of a Centrifugal Pump With Radial Gap Variation

2003 ◽  
Author(s):  
Jose´ Gonza´les ◽  
Carlos Santolaria ◽  
Jorge Luis Parrondo ◽  
Joaqui´n Ferna´ndez ◽  
Eduardo Blanco
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Numerical Study ◽  
Unsteady Forces ◽  
Flow Rates ◽  
Blade Passage ◽  
Pressure Distributions ◽  
Dynamic Forces ◽  
Radial Forces ◽  
Radial Gap

An experimental and numerical study is presented on the unsteady radial forces produced in a centrifugal pump with volute casing. Two impellers with different outlet diameter were considered, which gave radial gaps between blade and tongue of 10% and 15.8% of the impeller radius, respectively. Firstly, the data from pressure fluctuation measurements was processed to obtain the dynamic forces at the blade-passage frequency, for a number of flow-rates. Afterwards, these results were used to check the predictions from a numerical simulation of the pump with the code Fluent. This paper describes the work carried out and summarizes the experimental and the numerical results, for both radial gaps. The steady and unsteady forces at the blade passing frequency obtained by radial integration of the pressure distributions in the shroud side of the pump volute are analysed in detail and similar trends are obtained.

scholarly journals Analysis of Radial Force and Vibration Energy in a Centrifugal Pump

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Baoling Cui ◽  
Jiacheng Li ◽  
Chenliang Zhang ◽  
Yingbin Zhang
Keyword(s):  
Centrifugal Pump ◽  
Entropy Generation ◽  
Radial Force ◽  
Entropy Generation Rate ◽  
Vibration Energy ◽  
Hydraulic Loss ◽  
Flow Rates ◽  
The Poor ◽  
Radial Forces ◽  
Design And Manufacture

Vibration is one of the main issues taken into consideration in the design and manufacture of the pump. The radial force and vibration of the impeller induced by fluid in a centrifugal pump were investigated at different flow rates by numerical simulation. The vibrations on the volute were measured by the experiment. The variation trend of the radial displacements of the impeller is consistent with that of the radial forces, and the variation in the radial displacement lags that of the radial force. The vibration energies on the impeller and the volute were analyzed based on root-mean-square (RMS) values in the frequency domain. The distributions of energy loss in the pumps were calculated to determine the total entropy generation (TEG) and entropy generation rate (EGR). The TEG values as calculated are in close accordance with hydraulic loss. The vibration is a result of the poor flow patterns and consequently results in increased energy losses in the pump.

Experimental and Numerical Investigation of a Centrifugal Pump Working as a Turbine

2009 ◽  
Author(s):  
Joaqui´n Ferna´ndez ◽  
Rau´l Barrio ◽  
Eduardo Blanco ◽  
Jorge Parrondo ◽  
Alfonso Marcos
Keyword(s):  
Numerical Investigation ◽  
Centrifugal Pump ◽  
Static Pressure ◽  
Maximum Amplitude ◽  
Radial Force ◽  
Local Flow ◽  
Sliding Mesh ◽  
Static Pressure Distribution ◽  
Numerical Predictions ◽  
Radial Forces

An experimental and numerical investigation of a conventional centrifugal pump working as a turbine is presented. The numerical simulations were performed with the code Fluent by means of unsteady flow calculations and a sliding mesh technique to account for the impeller-volute interactions. Thus, it was possible to properly simulate the effect on the local flow of the passage of the impeller blades in front of the volute tongue. The numerical results were compared with the experimentally determined performance curves and additionally with the static pressure distribution measured around the impeller periphery. Once validated, the model was used to estimate the steady and unsteady radial forces on the impeller for a number of flow rates. The steady radial force was also experimentally estimated from the static pressure measurements around the periphery of the impeller. The numerical predictions showed that, for the flow interval considered in the present investigation, the unsteady radial force varied between 24% and 54.3% of the steady magnitude, and that its maximum amplitude was reached when the trailing edge of one of the blades was located 3 deg downstream the tip of the tongue.

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.

Experimental Study of the Flow in the Suction Pipe of a Centrifugal Pump at Partial Flow Rates in Unsteady Conditions

1999 ◽  
Vol 121 (3) ◽  
pp. 291-295 ◽  
Author(s):  
S. Bolpaire ◽  
J. P. Barrand
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Static Pressure ◽  
Pressure Measurements ◽  
Flow Rates ◽  
Suction Pipe ◽  
Start Up ◽  
Test Loop ◽  
Fast Start ◽  
Operational Range

The operational range and the performances of pumps are limited by the occurrence of backflow and prerotation in the suction pipe as the flow rate is reduced. This paper presents the study of static pressure measurements and visualizations in the suction pipe, near the inlet of a centrifugal pump, at partial flow rates, in steady conditions, and during a fast start-up of the pump. The tests were carried out in water on the DERAP© test loop of the ENSAM Lille laboratory. Standard methods allowed to determine the recirculation critical flow rate. A visualization method showed that the axial extent of the recirculation and the prerotation with the flow rate is considerably reduced during a fast start-up compared to steady conditions.

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