Statistical characteristics of suction pressure signals for a centrifugal pump under cavitating conditions

Li, Xiaojun; Yu, Benxu; Ji, Yucheng; Lu, Jiaxin; Yuan, Shouqi

doi:10.1007/s11630-017-0908-9

Cited by 27 publications

(14 citation statements)

References 6 publications

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“…At present, there are several methods for detecting cavitation inception that are the energy method [5], optical method [6], surface coating method [7], electrical resistance method [8], acoustic emission technology [9,10], and vibroacoustic method [11,12]. With a head drop of 3% or an efficiency drop of 1% as the criterion, the energy method could cause an erroneous estimate because actually the cavitation has developed to a certain extent under these conditions.…”

Section: Introductionmentioning

confidence: 99%

Detection of Inception Cavitation in Centrifugal Pump by Fluid‐Borne Noise Diagnostic

Zhao

Dai

2019

Shock and Vibration

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This paper presents an experimental methodology that is capable of sensitively detecting the cavitation inception in a centrifugal pump. Firstly, with a centrifugal pump of ns=117 as research object, the cavitation performance, the bubble pattern distribution at impeller inlet, and the vibration and noise were synchronously measured at different flow conditions each with several cavitation coefficients. The change laws of total level of vibration and noise signals throughout the cavitation process were emphatically investigated. After comparing the sensitivity and reliability of different detection methods, the method based on overall sound pressure level of liquid-borne noise is found to present high sensitivity to cavitation. Secondly, by comparing the affected 1/3 octave spectrum by changing flow and cavitation coefficients, the highly sensitive frequency band to cavitation was obtained. Then, a new inception cavitation detection method was proposed based on Pauta principle. Finally, the method was verified through an ultra-low-specific speed pump (ns=25). The results show that the total pressure level of liquid-borne noise increases firstly and then decreases with the development of cavitation. The broadband SPL of liquid-borne noise between 2000 and 3000 Hz can be used to detect the inception cavitation, and the cavitation detection threshold is determined as 1.0%.

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Section: Introductionmentioning

confidence: 99%

Detection of Inception Cavitation in Centrifugal Pump by Fluid‐Borne Noise Diagnostic

Zhao

Dai

2019

Shock and Vibration

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“…With the development of acoustic field calculating method, there are three means for noise calculation. [19][20][21] (1) The direct calculating method-the basic idea is to solve the noise directly by hydrodynamics and it can only be solved by detached eddy simulation (DES) and large eddy simulation (LES) methods. (2) Semi-empirical model method-the basic idea is to solve the flow field information based on Reynolds average equation first and acoustic field is then solved based on semi-empirical formula.…”

Section: Introductionmentioning

confidence: 99%

Research on cavitation acoustic characteristics of centrifugal pump based on fluid-acoustic field coupling method

Zhao

Dai

et al. 2018

Advances in Mechanical Engineering

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In order to study the change rules of interior acoustic field with the development of cavitation, this article presented a method that through comparing the experiment results with numerical simulation results in cavitation bubbles' distribution images under different cavitation coefficients to optimize the accuracy of acoustic field simulation using computational fluid dynamics combined with the Lighthill acoustic analogy. First, a closed visual testing system was established based on pump product test system and high-speed photography. Second, the cavitation performance under the rated operating condition was calculated using different cavitation models, in order to obtain both pump cavitation performance curve and distribution of cavitation bubbles. Next, based on the external characteristics experiment and highspeed photography experiment, the appropriate cavitation model for unsteady numerical calculation was selected. On the basis of vapor volume fraction distribution and the cavitation performance curve, four different typical points representing different cavitation coefficients were selected for further analyses. The direct boundary element method was used to calculate the variation characteristics of cavitation-induced noise at different cavitation coefficients. Finally, the peak-to-peak value of pressure fluctuation coefficient is defined as E, and the pressure pulsating frequency domain signals were analyzed to further study the influence of pressure pulsation on acoustic field. The results show that the effect of pressure pulsation on noise is mainly focused on the discrete eigenvalues, and as for the broadband noise, the influence is not obvious. With the development of cavitation, axial passing frequency, 10-to 100-Hz frequency band, and 1000-to 3000-Hz frequency band show an increasing trend, while blade passing frequency and its harmonic frequencies show a decreasing trend. At the onset of cavitation, 1000-to 3000-Hz frequency band has the highest sensitivity for cavitation detection.

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“…It is necessary to verify the independence of the centrifugal pump grid [21][22][23]. Generally speaking, if the geometry model is correctly meshed, the Reynolds-Average Navier-Stokes-based turbulence simulation result will not fluctuate significantly as the number of model grids increases.…”

Section: Methods Validationmentioning

confidence: 99%

Numerical Study on the Influence of Inlet Guide Vanes on the Internal Flow Characteristics of Centrifugal Pump

Lin

et al. 2020

Processes

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In order to make the centrifugal pump run efficiently and stably under various working conditions, the influences of the incoming vortex flow in the inlet pipe on the main flow in the impeller is studied numerically, based on the k − ω SST turbulence model. Some guide vanes with different offset angle were added to change the statistical characteristic of the internal flow in the inlet pipe of the centrifugal pump. Both contour distributions of internal flow and statistical results of external performance are obtained and analyzed. The results show that the existence of vanes can divide the large vortex because of the reversed flow from the rotating impeller at low flow rate conditions into small vortices, which are easier to dissipate, make the velocity and pressure distribution more uniform, improve the stability of the flow in the impeller, reduce the hydraulic loss, and improve the hydraulic performance of the pump. The pump with vanes of offset angle 25° has a small pressure pulsation amplitude at each monitoring point. Comparing with the performance of the original pump, the head increased by around 2% and efficiency increased by around 2.5% of the pump with vanes of offset angle 25°.

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Statistical characteristics of suction pressure signals for a centrifugal pump under cavitating conditions

Cited by 27 publications

References 6 publications

Detection of Inception Cavitation in Centrifugal Pump by Fluid‐Borne Noise Diagnostic

Detection of Inception Cavitation in Centrifugal Pump by Fluid‐Borne Noise Diagnostic

Research on cavitation acoustic characteristics of centrifugal pump based on fluid-acoustic field coupling method

Numerical Study on the Influence of Inlet Guide Vanes on the Internal Flow Characteristics of Centrifugal Pump

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