Effect of the Volute Diffuser Shape on Pressure Pulsations and Radial Force in Centrifugal Pumps

2017 ◽  
pp. 603-612
Author(s):  
Issa Chalghoum ◽  
Noura Bettaieb ◽  
Sami Elaoud
Keyword(s):  
Radial Force ◽  
Centrifugal Pumps ◽  
Pressure Pulsations

scholarly journals Cavitating flow-induced unsteady pressure pulsations in a low specific speed centrifugal pump

2018 ◽  
Vol 5 (7) ◽  
pp. 180408 ◽  
Author(s):  
Ning Zhang ◽  
Bo Gao ◽  
Zhong Li ◽  
Qifeng Jiang
Keyword(s):  
Critical Point ◽  
Cavitation Bubble ◽  
Pressure Wave ◽  
High Energy ◽  
Cavitation Number ◽  
Centrifugal Pumps ◽  
Pressure Pulsations ◽  
Measuring Point ◽  
Number Range ◽  
Cavitation Region

With the development of cavitation, the high-energy pressure wave from a cavitation bubble collapsing is detrimental to the stable operation of centrifugal pumps. The present paper concentrates on pressure pulsations under cavitation conditions, and pressure amplitudes at the blade-passing frequency ( f BPF ) and RMS values in the 0–500 Hz frequency band are combined to investigate cavitation-induced pressure pulsations. The results show that components at f BPF always dominate the pressure spectrum even at the full cavitation stage. For points P1–P7 on the volute side wall, with a decreasing cavitation number, the pressure energy first remains unchanged and then it rises rapidly after the critical point. For point In1 in a volute suction pipe located close to the cavitation region, the pressure energy changes slightly at high cavitation numbers; then for a particular cavitation number range, the pressure energy decreases, and finally increases again. For different flow rates, the pressure energy at the critical point is much lower than the initial amplitude at the non-cavitation condition for In1. This demonstrates that the cavitation cloud in the typical stage is partially compressible, and the emitted pressure wave from a collapsing cavitation bubble is absorbed and attenuated significantly. Finally, this leads to the pressure energy decreasing rapidly for the measuring point In1 near the cavitation region.

Clocking effect in a centrifugal pump with a vaned diffuser

2020 ◽  
Vol 34 (26) ◽  
pp. 2050286
Author(s):  
Fen Lai ◽  
Xiangyuan Zhu ◽  
Yongqiang Duan ◽  
Guojun Li
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Loss ◽  
Total Pressure ◽  
Radial Force ◽  
Design Flow ◽  
Total Pressure Loss ◽  
Inlet Section ◽  
Centrifugal Pumps ◽  
Installation Angle

The performance and service life of centrifugal pumps can be influenced by the clocking effect. In this study, 3D numerical calculations based on the k-omega shear stress transport model are conducted to investigate the clocking effect in a centrifugal pump. Time-averaged behavior and transient behavior are analyzed. Results show that the optimum diffuser installation angle in the centrifugal pump is [Formula: see text] due to the minimum total pressure loss and radial force acting on the impeller. Total pressure loss, particularly in the volute, is considerably influenced by the clocking effect. The difference in total pressure loss in the volute at different clocking positions is 2.75 m under the design flow rate. The large total pressure loss in the volute is primarily caused by the large total pressure gradient within the vicinity of the volute tongue. The radial force acting on the impeller is also considerably affected by the clocking effect. When the diffuser installation angle is [Formula: see text], flow rate fluctuations in the volute and impeller passage are minimal, and flow rate distribution in the diffuser passage is more uniform than those in other diffuser installation angles. Moreover, static pressure fluctuations in the impeller midsection and the diffuser inlet section are at the minimum value. These phenomena explain the minimum radial force acting on the impeller. The findings of this study can provide a useful reference for the design of centrifugal pumps.

scholarly journals Numerical Research on Hydraulically Generated Vibration and Noise of a Centrifugal Pump Volute with Impeller Outlet Width Variation

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Houlin Liu ◽  
Jian Ding ◽  
Hanwei Dai ◽  
Minggao Tan ◽  
Xiaochen Tang
Keyword(s):  
Noise Level ◽  
Sound Radiation ◽  
Fem Analysis ◽  
Centrifugal Pumps ◽  
Pressure Pulsations ◽  
Performance Pressure ◽  
Impeller Outlet ◽  
Numerical Research ◽  
Structure Vibration ◽  
Vibration And Sound Radiation

The impeller outlet width of centrifugal pumps is of significant importance for numbers of effects. In the paper, these effects including the performance, pressure pulsations, hydraulically generated vibration, and noise level are investigated. For the purpose, two approaches were used to predict the vibration and sound radiation of the volute under fluid excitation force. One approach is the combined CFD/FEM analysis for structure vibration, and then the structure response obtained from the FEM analysis is treated as the boundary condition for BEM analysis for sound radiation. The other is the combined CFD/FEM/BEM coupling method. Before the numerical methods were used, the simulation results were validated by the vibration acceleration of the monitoring points on the volute. The vibration and noise were analyzed and compared at three flow conditions. The analysis of the results shows that the influences of the sound pressure of centrifugal pumps on the structure appear insignificant. The relative outlet widthb2*atnq(SI) = 26.7 in this paper should be less than 0.06, based on an overall consideration of the pump characteristics, pressure pulsations, vibration and noise level.

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.

Computational Study of Pressure Pulsation in a Medium Specific Speed Pump

2005 ◽  
Author(s):  
Serguei Timouchev
Keyword(s):  
Complex Geometry ◽  
Computational Study ◽  
Spectral Component ◽  
Axial Component ◽  
Centrifugal Pumps ◽  
Pressure Pulsations ◽  
3 Dimensional ◽  
Order Of Magnitude ◽  
Specific Speed ◽  
In The Beginning

The centrifugal pump of high specific speed with a diagonal type of impeller flow is studied experimentally and numerically. Both 2D and 3D numerical methods are used by applying acoustics–vortex equations. Increasing energetic parameters of centrifugal pumps requires a more complex geometry of the impeller and volute as one needs to raise the specific speed of the pump to provide a higher efficiency value. The pump of higher specific speed has an impeller with curved blades and diagonal meridional section. The flow outgoing the impeller has an essential axial component of velocity. Thus the two dimensional approach will not give the accurate prediction of pressure pulsations in the volute casing. This is why the new 3-dimensional method has been elaborated for this task. The 3D computational results of pressure pulsations are compared with those obtained by 2D-computation Measurements show that in the beginning of volute, in the pseudo-sound zone, amplitude of Blade Passing Frequency (BPF) spectral component is higher than that at the pump outlet by an order of magnitude. The 3-Dimensional analysis gives a good agreement with experimental data while the 2D prediction underestimates the BPF amplitude in the beginning of volute.

Study on radial force characteristics of double-suction centrifugal pumps with different impeller arrangements under cavitation condition

2020 ◽  
pp. 095765092092682
Author(s):  
Yu Song ◽  
Honggang Fan ◽  
Zhenwei Huang
Keyword(s):  
Strong Influence ◽  
Radial Force ◽  
Force Distribution ◽  
Centrifugal Pumps ◽  
Cavitation Model ◽  
Cavitation Phenomenon ◽  
Cavitation Performance ◽  
Critical Cavitation ◽  
Force Characteristics ◽  
Different Parts

Cavitation phenomenon is inevitable in pumps with strong transient characteristics. Due to the presence of vapors, the pressure distribution in the impeller changes greatly, resulting in a different radial force distribution from that in non-cavitation condition. In the present article, the cavitation performance of double-suction pumps with different impeller–vane arrangements is studied using the renormalization group k–& turbulence model and the Zwart–Gerber–Belamri cavitation model. The radial force on the two impellers and the whole pump are calculated and compared under critical cavitation conditions. The radial force on different parts of impellers is investigated in detail. A strong influence of the radial force on the blades is detected for different impeller–vane arrangements. Then, the flow characters are analyzed in the mid-span of volute. The results show that axial flows are detected in volute near the outlet of the impellers, which is the main cause of the “two-impeller-interaction”.

Radial Force on the Impeller of Centrifugal Pumps With Volute, Semivolute, and Fully Concentric Casings

1965 ◽  
Vol 87 (3) ◽  
pp. 319-322 ◽  
Author(s):  
H. Joseph Biheller
Keyword(s):  
Experimental Investigation ◽  
Centrifugal Pump ◽  
Radial Force ◽  
Operating Speed ◽  
Centrifugal Pumps ◽  
Operating Range ◽  
Aspect Ratios ◽  
Radial Forces

An experimental investigation of the magnitude and direction of the unbalanced radial force on centrifugal pump impellers was made. Pumps with single volute, semiconcentric and fully concentric casings of several specific speeds, collector aspect ratios, and with both closed and semiclosed impellers were tested over the full operating range. An equation enabling prediction of expected radial forces based only on pump geometry, operating speed, and capacity (expressed as fraction of capacity at best efficiency) is presented.

Performance and Radial Loading of a Mixed-Flow Pump Under Non-Uniform Suction Flow

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
B. P. M. van Esch
Keyword(s):  
Velocity Profile ◽  
Radial Force ◽  
Rotor System ◽  
Flow Profile ◽  
Centrifugal Pumps ◽  
Mixed Flow ◽  
Pipe Bend ◽  
Suction Velocity ◽  
Suction Flow ◽  
Flow Pump

Many centrifugal pumps have a suction velocity profile, which is nonuniform, either by design like in double-suction pumps, sump pumps, and in-line pumps, or as a result of an installation close to an upstream disturbance like a pipe bend. This paper presents an experimental study on the effect of a nonuniform suction velocity profile on performance of a mixed-flow pump and hydrodynamic forces on the impeller. In the experiments, a newly designed dynamometer is used, equipped with six full Wheatstone bridges of strain gauges to measure the six generalized force components. It is placed in between the shaft of the pump and the impeller and corotates with the rotor system. A high accuracy is obtained due to the orthogonality of bridge positioning and the signal conditioning electronics embedded within the dynamometer. The suction flow distribution to the pump is adapted using a pipe bundle situated in the suction pipe. Results of measurements show the influence of the suction flow profile and blade interaction on pump performance and forces. Among the most important observations are a backward whirling motion of the rotor system and a considerable steady radial force.

scholarly journals FORECASTING THE VIBRATIONAL STATE OF AN ELECTRIC PUMP AGGREGATE

2020 ◽  
Vol 3 (51) ◽  
pp. 19-25
Author(s):  
M. Sotnyk ◽  
V. Moskalenko ◽  
A. Sokhan ◽  
D. Sukhostavets
Keyword(s):  
Experimental Research ◽  
Vibration Velocity ◽  
Electric Pump ◽  
Centrifugal Pumps ◽  
Pressure Pulsations ◽  
Working Process ◽  
Blade Vibration ◽  
Pump Aggregate ◽  
Blade Frequency ◽  
Rms Amplitude

Purpose. The operation of electromechanical systems (EMS) in off-design modes and in which centrifugal pumps are used is accompanied by a number of negative factors, a special place among which is occupied by excessive blade vibration of the pump, which negatively affects its operational characteristics and causes a reduction in the service life of the main EMS units. Thus, an urgent task is to improve the operating characteristics of the pump as a component of EMS, which, by increasing the energy efficiency of the EMS working process and/or reducing the total cost of the life cycle of the pumps in their composition, will ultimately have a significant economic effect. Methodology. Experimental research of working process of an electric pump aggregate type D according to DSTU 6134:2009 and ISO 10816-3:2014. Results. Based on the experimental research results of vibration state of the pump D2000-100-2 bearing shell, which operates as part of the EMS, and the intensity of fluid pressure pulsations at its outlet, the limit root mean square value (RMS) of the pressure pulsation amplitude (∆Р ≥ 35,8 kPa and/or 3,4 % Н) is set at which an excess of the established ISO 10816: 3-2014 limit RMS of vibration velocity of the pump bearing shell ( V  2,8 mm/s ) and also is determined correlation coefficient ( / л k V Р ), which characterizes the RMS of the vibration velocity of the pump bearing shell at the blade frequency ( Vл ) depending on the RMS amplitude of the blade pressure pulsations (∆Р). Practical value. Since the number and systematic of experimental researches of the effect of pump parameters on the intensity of its blade vibration is complicated by the high cost of their implementation, therefore, it is advisable in further researches to use the RMS amplitude of blade pressure pulsations as an indirect indicator of the RMS vibration velocity of the pump bearing shell at the blade frequency. Conclusion. The intensity of pressure pulsations and influence of main parameters of the pump on their amplitude, with sufficient accuracy for engineering calculations can be determined by numerical modeling of the unsteady fluid flow in the flowing part of the pump. Figures 5, tables 2, references 10.

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