Identification of Critical Net Positive Suction Head From Noise and Vibration in a Radial Flow Pump for Different Leading Edge Profiles of the Vane

Stephen, Christopher; Kumaraswamy, S.

doi:10.1115/1.4025072

Cited by 44 publications

(28 citation statements)

References 14 publications

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“…Cavitation first occurs locally at the low pressure region in the impeller and develops in accordance with the decrease of suction pressure in a pump [1]. As an important energy transforming device and fluid conveying equipment, centrifugal pumps are widely used in various fields [2].…”

Section: Introductionmentioning

confidence: 99%

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Research on the characteristics of quasi-steady cavitation in a centrifugal pump

Yuan

et al. 2015

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. With the pressure decreasing, the process of cavitation in a centrifugal pump could be summarized as incipient cavitation, quasi-steady cavitation and unsteady cavitation. Quasi-steady cavitation is the condition that is between the incipient cavitation and unsteady cavitation in a centrifugal pump. Under this condition, the intensity of cavitation is relatively weak, and the head of the pump almost remains unchanged, but the cavitation exists, causing damage to the impeller by pitting and erosion. So it is important to investigate the quasi-steady cavitation. In this paper, both the numerical and experimental methods had been carried out to investigate the characteristics of quasi-steady cavitation. The internal flow in the pump, the performance of cavitation and the inlet and outlet pressure pulsation of the pump measured through experimental method have been studied under different NPSHa conditions. It was found that the head decreases about 0.77%-1.38% from non-cavitation condition and it could be regarded as the quasi-steady cavitation. Little change has been found from the internal flow between non-cavitation condition and quasi-steady cavitation condition. The period of inlet pressure pulsation changes from the time that the blade passes by to the period of shaft rotating with the development of cavitation. The dominant frequency of the inlet pressure pulsation is two times of shaft frequency whose amplitudes decrease firstly and then increase to a peak value, followed by a decrease to a low value in quasi-steady cavitation conditions. The dominant frequency of the outlet pressure pulsation is blade passing frequency whose amplitudes increase firstly and then decrease gradually with the decrease of NPSHa.

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Section: Introductionmentioning

confidence: 99%

“…Inception of cavitation occurs when the static pressure of the liquid at any location is lower than the saturated vapor pressure of that liquid at the prevailing temperature in the presence of nuclei [1]. 3 Corresponding author.…”

Section: Introductionmentioning

confidence: 99%

Research on the characteristics of quasi-steady cavitation in a centrifugal pump

Yuan

et al. 2015

IOP Conf. Ser.: Mater. Sci. Eng.

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“…For pump design, the required NPSH (NPSH r ) is used that is usually experimentally measured by NPSH for 3% head drop (NPSH head,3% ) or NPSH for 1% efficiency drop (NPSH eff.,1% ) and the NPSH a should be greater than NPSH r in order to avoid pump cavitation. 3 Many researchers have predicted the inception and development of cavitation through the experiments and numerical simulations. The process of cavitation is usually determined by two criterions (NPSH head,3% and NPSH eff.,1% ).…”

Section: Introductionmentioning

confidence: 99%

“…Then some negative effects may be caused by its unsteady and erosive characteristics, such as noise, vibration, performance reduction, and erosion. [2][3][4][5] The occurrences of these negative effects are not at the same time but step by step with the development of cavitation. Therefore, it is very important to understand the inception and development of cavitation in the pump in order to prevent cavitation.…”

Section: Introductionmentioning

confidence: 99%

Simulation of cavitation performance of an axial flow pump with inlet guide vanes

Feng

Cheng

Guo

2016

Advances in Mechanical Engineering

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The cavitation performance of an axial flow pump with inlet guide vanes for different flow rates is studied in this article. The effects of inlet guide vanes on pump hydraulic performance and cavitation are investigated, where the total vapor fraction of impeller zone (F tv ) is calculated to predict the critical net positive suction head, which is compared with that predicted by efficiency criterion for different flow rates. The influences of the development of cavitation on internal flow in impeller zone are also investigated. The results obtained show that the cavitation performance of axial flow pump can be improved at off-design flow conditions by adjusting angles of inlet guide vanes to positive values at low flow rates and by regulating angles of inlet guide vanes to negative values at high flow rates. As the net positive suction head decreases, the vapor fraction first increases slowly and then increases greatly, clearly presenting cavitation process from inception to full development, which can be used to predict the required net positive suction head. When net positive suction head decreases to the value around required net positive suction head, the cavitation zone from tip of blade suction side close to leading edge and the cavitation zone from hub part of the blade suction side connect together. After the connection, the cavitation zones have great influence on the velocity flow, leading to the decrease in pump performance.

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“…But many researches have proved that cavitation develops much earlier than that reflected in the head curve [9,10]. Visualization of cavitation inside the blade channels could be applied to observe cavitation inception effectively, but it is not a convenient means in industrial application [11].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on Cavitating Flow Induced Vibration Characteristics of a Low Specific Speed Centrifugal Pump

Gao

Guo

Zhang

et al. 2017

Shock and Vibration

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Cavitating flow developing in the blade channels is detrimental to the stable operation of centrifugal pumps, so it is essential to detect cavitation and avoid the unexpected results. The present paper concentrates on cavitation induced vibration characteristics, and special attention is laid on vibration energy in low frequency band, 10-500 Hz. The correlation between cavitating evolution and the corresponding vibration energy in 10-500 Hz frequency band is discussed through visualization analysis. Results show that the varying trend of vibration energy in low frequency band is unique compared with the high frequency band. With cavitation number decreasing, vibration energy reaches a local maximum at a cavitation number much larger than the 3% head drop point; after that it decreases. The varying trend is closely associated with the corresponding cavitation status. With cavitation number decreasing, cavitation could be divided into four stages. The decreasing of vibration energy, in particular cavitation number range, is caused by the partial compressible cavitation structure. From cavitation induced vibration characteristics, vibration energy rises much earlier than the usual 3% head drop criterion, and it indicates that cavitation could be detected in advance and effectively by means of cavitation induced vibration characteristics.

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Identification of Critical Net Positive Suction Head From Noise and Vibration in a Radial Flow Pump for Different Leading Edge Profiles of the Vane

Cited by 44 publications

References 14 publications

Research on the characteristics of quasi-steady cavitation in a centrifugal pump

Research on the characteristics of quasi-steady cavitation in a centrifugal pump

Simulation of cavitation performance of an axial flow pump with inlet guide vanes

Experimental Investigation on Cavitating Flow Induced Vibration Characteristics of a Low Specific Speed Centrifugal Pump

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