Time‐Frequency Characterization of Rotating Instabilities in  a Centrifugal Pump with a Vaned Diffuser

Pavesi, Giorgio; Cavazzini, Giovanna; Ardizzon, Guido

doi:10.1155/2008/202179

Cited by 32 publications

(12 citation statements)

References 23 publications

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“…In a similar way, Bousquet et al [11] found that 6 vortices are formed and shed per revolution in their centrifugal compressor, thus being responsible of a observed tone at six times compressor rotational frequency. Besides, Pavesi et al [38] attributed a tone corresponding to 66% of impeller rotation to a sequence of vortices in the wake region originated at blade midchord in a centrifugal pump with vaned diffuser. Figure 11 corresponds to 77 g/s operating conditions.…”

Section: Flow Field Investigationmentioning

confidence: 99%

Numerical and experimental analysis of automotive turbocharger compressor aeroacoustics at different operating conditions

Broatch

Galindo

Garcia

et al. 2016

International Journal of Heat and Fluid Flow

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Centrifugal compressor aeroacoustics are analyzed by means of a 3-dimensional CFD model. Three operating points at nominal compressor speed are simulated ranging from best efficiency point to near-surge conditions. Experimental measurements are obtained using a steady flow rig mounted on an anechoic chamber. URANS and DES predictions of compressor global variables and pressure spectra are compared against experimental measurements. Flow-induced noise increases as the operating point moves towards surge line. Stall at the suction side of the blades exists even for high mass flow conditions, causing a high frequency boundary layer oscillation. Low momentum cells rotating at the diffuser are found at points closer to surge, causing the so-called whoosh noise. Inducer rotating stall is also present at these conditions. Point closest to surge shows a rotating tornado-type vortex at the inducer, determining a moving low pressure region that increases low frequency noise content.

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Section: Flow Field Investigationmentioning

confidence: 99%

Numerical and experimental analysis of automotive turbocharger compressor aeroacoustics at different operating conditions

Broatch

Galindo

Garcia

et al. 2016

International Journal of Heat and Fluid Flow

View full text Add to dashboard Cite

show abstract

“…Yao [29] analysed the unsteady structure of the pressure fluctuation by using many methods, including wavelet transform, short-time Fourier transform. Pavesi et al [30] performed a spectral analysis of the pressure fluctuation signal and applied the wavelet analysis method to evaluate the pressure fluctuations transient characteristics. Previous studies [31,32] have also used wavelet correlation to analyse the unique capability for decomposing the correlation of arbitrary signals.…”

Section: Continuous Wavelet Transformmentioning

confidence: 99%

Experimental Investigation of Transient Characteristics of a Double Suction Centrifugal Pump System during Starting Period

Jin

Yao

et al. 2019

Energies

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The starting phase for pumps in water transportation pipelines is crucial and has significant transient characteristics which merit further study in order to evaluate the operational stability of the pumping system. This paper presents the results of a study in which the relative steady operating conditions and starting period of a large double-suction centrifugal pump were monitored in real time, including pressure fluctuations, shaft run-out and vibration at the bearing. The transient characteristics of a double-suction centrifugal pump under different operating conditions have been analyzed using fast Fourier transform (FFT) and continuous wavelet transform (CWT). Results indicate broadband frequency components within the spectrum of pressure fluctuations in the volute casing under all test conditions, and the central frequency of the broadband frequency gradually decreases as flow rate increases and approaches the blade frequency, which is the primary reason for an increase in blade-frequency amplitude. This may produce a vibration frequency that is similar to the natural frequency of a certain part of the double-suction centrifugal pump during the starting period, which causes the resonance phenomenon. The radial force is also large during the starting period, which causes eccentric wear of the seal ring at the impeller inlet.

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“…The flow field into the wickets gates channel starts to manifest a full three-dimensional flow structure. These disturbances, related to the boundary layer separation and stall, were noticed with images of the amplitude at a frequency very close to the impeller frequency St = 0.143 and to the sub-tonal frequency St « 0.335 identified by experimental measurements [24][25][26] also in steady conditions. With a further reduction of the impeller speed, the rotating partial stall rules the interactions.…”

Section: Numerical Analysis Of the Pump-turbine In A Power Reduction mentioning

confidence: 99%

Numerical Analysis of the Transient Behaviour of a Variable Speed Pump-Turbine during a Pumping Power Reduction Scenario

2016

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To achieve the carbon free electricity generation target for 2050, the penetration of renewable energy sources should further increase. To address the impacts of their unpredictable and intermittent characteristics on the future electricity grid, Pumped Hydro Energy Storage (PHES) plants should enhance their regulation capability by extending their continuous operating range far beyond the optimal normal working range. However, for the time being, the regulation capability of the new generation of PHES, equipped with reversible pump-turbines due to their cost-effectiveness, is limited at part load by instability problems. The aim of this paper is to analyse, during a pumping power reduction scenario, the onset and development of unsteady phenomena leading to unstable behaviour. A 3D transient numerical simulation was carried out on the first stage of a variable-speed two-stage pump-turbine from full load to the unstable operating zone by progressively reducing the speed from 100% to 88% rpm corresponding to a power reduction from full load to about 60% with a ramp rate of 1.5% per s. Two three-dimensional unsteady flow structures affecting the return channel and the wicket gates at the end of the first stage were identified and their evolution in the power regulation scenario was fluid-dynamically and spectrally characterized to determine the fluid-dynamical conditions causing the head drop in the hump zone.

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Time‐Frequency Characterization of Rotating Instabilities in a Centrifugal Pump with a Vaned Diffuser

Cited by 32 publications

References 23 publications

Numerical and experimental analysis of automotive turbocharger compressor aeroacoustics at different operating conditions

Numerical and experimental analysis of automotive turbocharger compressor aeroacoustics at different operating conditions

Experimental Investigation of Transient Characteristics of a Double Suction Centrifugal Pump System during Starting Period

Numerical Analysis of the Transient Behaviour of a Variable Speed Pump-Turbine during a Pumping Power Reduction Scenario

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