Assessment of some stall-onset criteria for centrifugal compressors

Ghenaiet, Adel; Khalfallah, Smail

doi:10.1016/j.ast.2018.12.039

Cited by 28 publications

(14 citation statements)

References 30 publications

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“…It is also employed to optimize the blade design of compressors. 37 , 38 In this section, this method is applied in the analysis of unsteady flow in the impeller with various tip clearances. The blockage factor is defined as where A act is the total area of the cutting plane, ρW m is the meridional momentum, and ( ρW m ) edge is the edge momentum.…”

Section: Resultsmentioning

confidence: 99%

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Transient characteristics of internal flow fields of mixed-flow pump with different tip clearances under stall condition

Shi

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part A:

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This paper investigates the influence of different tip clearances on the transient characteristics of mixed-flow pump under stall condition. The instantaneous internal flow fields of mixed-flow pump with four tip clearances (0.2 mm, 0.5 mm, 0.8 mm and 1.1 mm) are explored by conducting unsteady time accurate simulations. Reynolds-averaged Navier-Stokes (RANS) equations are employed in the simulations and the results of computations are compared with experimental data. The results show that the pump head decreases by 22.1% and the pump efficiency drops by 13.9% at design flow condition when the impeller tip clearance increases from 0.2 mm to 1.1 mm. The swirling flow occurs in the inlet pipe of the mixed-flow pump with different tip clearances under stall condition, and the initial starting point of the swirling flow gets further away from the impeller inlet with increase in tip clearance because of increase in circumferential velocity and change in momentum of the tip leakage flow (TLF). The high turbulent eddy dissipation (TED) regions in the flow are attributed to the TLF, swirling flow, back flow and stall vortex, and their intensity are affected by the change in tip clearance. The oscillating trend of time domain distribution of TED enhances first and then decreases with increase in tip clearance and it exhibits a propagation feature under the effect of stall vortex, while most of the energy in the frequency domain remains concentrated in the low frequency part under stall condition.

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Section: Resultsmentioning

confidence: 99%

Section: Blockage Factor Distribution In Impeller For Different Tip Clearancesmentioning

confidence: 99%

Transient characteristics of internal flow fields of mixed-flow pump with different tip clearances under stall condition

Shi

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…Equation set (13)(14)(15)(16)(17) is solvable with the following boundary conditions: 15) can be simplified by Equation ( 17) if r = R; then the dispersion equation is obtained,…”

Section: Analysis Of the Propagation Velocity Coefficient Kmentioning

confidence: 99%

“…Bardelli et al [11] investigated the flow in the centrifugal stage of a compressor by different CFD models; unsteady phenomena captured by steady and unsteady simulations have been carefully compared with experimental data in the available literature. Among the instabilities in compressors, one unsteady flow phenomenon, which is known as a rotating stall, has been reported in both centrifugal [12][13][14] and axial [15][16][17][18] compressors. Moreover, a rotating stall can also be detected in different components even in the same system [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Stall Mode Transformation in the Wide Vaneless Diffuser of Centrifugal Compressors

Heng

Jiang

et al. 2020

Energies

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A review on the rotating stall in the vaneless diffuser of centrifugal compressors is presented showing that different stall modes characterized by different numbers of cells can be detected within the diffuser even if the operating condition remains unchanged. The interaction between the inlet perturbation and the stall cells near the diffuser outlet is supposed to be the trigger of the stall mode transformation. In order to determine if the inlet perturbation will interact with the downstream stall cells, a characteristic time analysis is proposed to estimate the characteristic time of the perturbation in radial and tangential directions. An additional theoretical model which focused on the development of the vaneless diffuser rotating stall is presented to determine the propagation velocity of the cells. The comparison between the characteristic time in two directions shows that one stall mode is able to evolve into another stall mode if a critical condition is met, and the stall mode transformation is more likely to start from a mode with a higher number of cells and is more likely to occur in the diffuser with a large radius ratio. Experimental results are also employed to validate the proposed critical condition, and good agreements are obtained.

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“…Research on the flow instability of the centrifugal compressor mainly focuses on the stall and surge. 32–34 Yang et al 35–37 and Zhang et al 38 suggested that a high pressure wave induced by the volute tongue can propagate backwards into the impeller inlet. He and Zheng 39 used the casing treatment device to eliminate the regional rotating instability and stall.…”

Section: Introductionmentioning

confidence: 99%

Investigation of tip leakage flow unsteadiness and rotating instability in a centrifugal compressor impeller

Wang

Yang

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part D:

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A phenomenon called rotating instability was rarely reported in a centrifugal compressor, although some associated discussions can be found in axial compressors. This paper presents a numerical investigation on the unsteadiness of the tip leakage flow and rotating instability in an isolated centrifugal compressor impeller. A three-dimensional, unsteady full annuls simulation is performed under three different operating conditions. The tip leakage flow unsteadiness at the impeller inlet and inside the impeller passage is detected by the pressure fluctuation. During the throttling process, the temporal and spatial propagation characteristic of the tip leakage flow unsteadiness under the near stall operating condition is revealed based on the wavelet analysis, Fourier transform, and dynamic mode decomposition. Furthermore, the relationship between the tip leakage flow unsteadiness and the rotating instability is also discussed. The results show that the pressure fluctuation mainly concentrates in the tip region at the near stall operating condition, which indicates the occurrence and circumferential propagation of tip leakage flow unsteadiness. The circumferential propagation of the tip leakage flow unsteadiness induces a significant circumferential rotating pressure wave with a wave number of 9 and approximately 48.2% of the rotational speed of the impeller. The characteristic frequency of the tip leakage flow unsteadiness agrees well with the dominant mode frequency of rotating instability. Therefore, the tip leakage flow unsteadiness is assumed to be responsible for the rotating instability. During the throttling process, the formation and development of the rotating instability at near stall operating condition can be divided into three stages based on signal analysis: prior to rotating instability, generation and development, and rotating instability.

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Assessment of some stall-onset criteria for centrifugal compressors

Cited by 28 publications

References 30 publications

Transient characteristics of internal flow fields of mixed-flow pump with different tip clearances under stall condition

Transient characteristics of internal flow fields of mixed-flow pump with different tip clearances under stall condition

Stall Mode Transformation in the Wide Vaneless Diffuser of Centrifugal Compressors

Investigation of tip leakage flow unsteadiness and rotating instability in a centrifugal compressor impeller

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