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.

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.

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.

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.

Efficient Design Method for Non-Synchronous Vibrations Using Enforced Motion

2008 ◽  
Author(s):  
Meredith A. Spiker ◽  
Robert E. Kielb ◽  
Kenneth C. Hall ◽  
Jeffrey P. Thomas
Keyword(s):  
Flow Instability ◽  
Design Method ◽  
Mode Frequency ◽  
Computational Time ◽  
Limit Cycle Oscillation ◽  
Efficient Design ◽  
Blade Vibration ◽  
Cycle Oscillation ◽  
Blade Frequency ◽  
Phase Angles

This paper presents the results of a new enforced motion method using harmonic balance computational fluid dynamics (CFD) analysis to design for NSV. Currently, most researchers employ a time domain CFD technique to directly find the frequency of the underlying flow instability which can take significant computational time. NSV is said to occur when the frequency of the instability coincides with a blade mode frequency. The enforced motion design method uses blade motion to attempt to force the fluid frequency to lock-on to the blade vibration frequency at a specified amplitude. For a fixed critical amplitude and blade mode frequency, a range of interblade phase angles (IBPAs) is investigated to determine the aerodynamic damping. A negative value of damping at any IBPA deems the design unacceptable. Furthermore, a procedure for blade re-design (frequency changing) is presented. At the least stable IBPA, the damping is determined for a range of blade frequencies and amplitudes to determine the Limit Cycle Oscillation (LCO) amplitude. A better design is then at the blade frequency that minimizes the blade vibration amplitude. Therefore, these preliminary results indicate that it is advantageous to include blade motion in NSV design approaches. Most significantly, it gives designers a quick and efficient method to assess a design for NSV.

Paper 12: Generation of Hydraulic Noise in Centrifugal Pumps

1966 ◽  
Vol 181 (1) ◽  
pp. 84-108 ◽  
Author(s):  
H. C. Simpson ◽  
R. Macaskill ◽  
T. A. Clark
Keyword(s):  
Rotational Speed ◽  
Pressure Fluctuations ◽  
Noise Spectrum ◽  
Operating Conditions ◽  
Frequency Noise ◽  
Test Results ◽  
Centrifugal Pumps ◽  
Blade Frequency ◽  
Good Agreement ◽  
Dominant Frequencies

The production of hydraulic noise by two types of centrifugal pumps—volute pumps and diffuser pumps—was examined to determine the effect of design and operating conditions on the level of noise generated in the pumped liquid. Experimental work with hydrophones in the exit and entrance to the pumps showed that for both pumps, the dominant frequencies in the noise spectrum were at rotational speed and blade number times rotational speed. It was also found that the distance between cutwater and impeller tip is critical in a volute pump as far as blade frequency noise is concerned. Analysis of the relation between the noise measured by the hydrophones and the fluctuating pressure produced by the pump and the water flow in the inlet and outlet ducts showed that the noise can be interpreted as being directly related to the unsteady flow of water issuing from the impeller. Test results of blade frequency noise levels were correlated with a theoretical analysis for static pressure fluctuations in the pump exit and were shown to be in good agreement. A correlation of general hydraulic noise level with pump specific speed and power consumption was also developed and shown to be reliable to within +2 dB.

OV6-38 x 2 MBK electric pump aggregate

1976 ◽  
Vol 12 (2) ◽  
pp. 192-193
Author(s):  
A. D. Dugach
Keyword(s):  
Electric Pump ◽  
Pump Aggregate

scholarly journals The Process of Operation of a Mobile Straw Spreading Unit with a Rotating Finger Body-Experimental Research

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1144
Author(s):  
Boris Boltianskyi ◽  
Radmila Sklyar ◽  
Natalia Boltyanska ◽  
Larysa Boltianska ◽  
Serhii Dereza ◽  
...  
Keyword(s):  
Experimental Data ◽  
Energy Consumption ◽  
Experimental Research ◽  
Rotation Speed ◽  
Bedding Material ◽  
Working Process ◽  
Spreading Process ◽  
Unit Speed ◽  
And Performance ◽  
Working Bodies

This article presents methods and results of experimental research to determine the power consumed when driving the working bodies of the straw bedding mobile spreader to cover cow stalls (boxes). Analysis of the design and mode parameters of the rotary finger working body influence on the energy consumption of the bedding material spreading process is carried out. Using the experimental data, it was established that the power consumed to drive the rotary finger working body of the mobile straw bedding spreader, at the tractor power take-off (PTO) shaft rotation speed of 540 min−1, the forward unit speed of 2 km/h, and performance of 1.5 kg/s, is equal to 7.633 kW. In this case, due to the installation of a rotary finger working body for spreading straw bedding, the power consumption increased by 9%. This increase will not have a significant impact on the overall energy consumption of the spreading bedding material working process, because this class tractor power reserve allows its use.

scholarly journals Variations of Performance and Pressure Pulsation During Cavitation in Centrifugal Pumps with Entrained Air

2021 ◽  
Vol 321 ◽  
pp. 04017
Author(s):  
Fanjie Deng ◽  
Jianping Yuan ◽  
Minquan Liao ◽  
Mengfei Chen ◽  
Han Zhu ◽  
...  
Keyword(s):  
Pressure Pulsation ◽  
Cavitation Number ◽  
Incoming Flow ◽  
Centrifugal Pumps ◽  
Cavitation Performance ◽  
Basic Law ◽  
Natural Cavitation ◽  
Blade Frequency ◽  
Entrained Air ◽  
The Military

Most of the research on the cavitation with entrained air has focused on the military direction, but it ,about centrifugal pumps, which is relevant to people's livelihood, is still relatively lacking. In order to study the basic law of the development of cavitation inside centrifugal pumps under aeration conditions, a test bench suitable for cavitation experiments with incoming flow containing gas was obtained. Furthermore, a single-stage single-suction 6-blade centrifugal pump was used as the research object to conduct pressure pulsation experiments under cavitation condition when the incoming flow was 1.0% air viod fraction at 2900r/min-50m3/h. The results showed that: After cavitation happened, the greater aeration content will deteriorate the pump's anti-cavitation performance, but the head curve is more gentle in falling down compared to natural cavitation. Hence aeration has a beneficial effect on the performance degradation of the pump under the cavitation condition. At the same time, before the cavitation number drops to the fracture cavitation number of the pump, aeration has improvement in the efficiency of the pump in different degrees , especially in the situation with the ventilated rate of 1.0%. The main frequency of pressure pulsation at the inlet and outlet of the test pump after aeration is dominated by the blade frequency. The shaft frequency signal at the outlet gradually decreases with the cavitation number lessened. Moreover the amplitude of the blade frequency grows slightly with the reduction of the cavitation number. But it tends to soar when the cavitation number is less than the fracture cavitation number.

Experimental and Numerical Analysis of Pressure Pulsations and Mechanical Deformations in a Centrifugal Pump Impeller

2011 ◽  
Author(s):  
Stefan Berten ◽  
Sebastian Hentschel ◽  
Karin Kieselbach ◽  
Philippe Dupont
Keyword(s):  
Boundary Conditions ◽  
Flow Behavior ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Pressure Waves ◽  
Centrifugal Pumps ◽  
Pressure Pulsations ◽  
Load Pressure ◽  
Part Load

Deformations, mechanical stresses and vibrations in centrifugal pumps are the result of pressure fluctuations, which are acting as excitation forces. When a pump operates at its optimum, the pressure pulsations are at minimum, but for a pump operating in part-load, pressure pulsations increase and subsequent vibration and deformation levels increase. In a recent experimental research, the pressure pulsations and the resulting structural stresses in the last stage impeller of a multistage pump have experimentally investigated for different operating conditions [1]. The experimental investigations have been complemented by transient numerical simulations using a commercial CFD code and structural analysis using the pressure pulsations resulting from the CFD code as boundary conditions. In the present study, a validation of these CFD and FEM simulations is presented. The analysis has been performed in three steps. In the first step, the transient CFD results for different load cases are analyzed and compared with the experimental results in order to evaluate the CFD simulations. In the second step the time domain pressure pulsation data are post-treated and decomposed into a series of rotating pressure waves. These pressure waves are then applied as boundary conditions to an FEM model and one full impeller revolution is simulated as steady calculations for 72 angular positions. The pressure pulsations in the best efficiency point are regularly distributed in space and time and dominated by rotor-stator-interaction. For part-load operation, the pressure distribution becomes more and more unsteady. The CFD results for part load exhibit stationary stall in the diffuser for a flow rate relative to best efficiency point of q* = 0.9 and unsteady stall behavior for a q* = 0.8. While the numerical CFD results agree well with experimental data for q* = 1 and q* = 0.9, at lower part load (q* = 0.8) the CFD didn’t reproduce the experimentally observed flow behavior, especially the rotating stall. The FEM results at design conditions show relatively low tangential stresses at the impeller outlet, which agree well with the measured deformations and stresses.

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