Numerical analysis of unstable turbulent flows in a centrifugal pump impeller considering the curvature and rotation effect

Ye, Weixiang; Zhu, Zuchao; Zhou, Qian; Luo, Xianwu

doi:10.1007/s12206-020-0619-0

Cited by 19 publications

(2 citation statements)

References 28 publications

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“…The occurrence of hydrodynamic cavitation is very common in hydraulic devices, such as hydrofoils, centrifugal pumps, turbines and propellers. It occurs as a result of a sudden and rapid decrease in pressure in a flowing fluid (Liang et al 2020;Ye et al 2020). In order to numerically predict cavitation erosion, it is necessary to model the coupling between turbulence and cavitation (Ji et al 2014;Cheng et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Numerical Prediction Approach of Cavitation Erosion based on 3D Simulation Flow

2022

JAFM

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In industry, the phenomenon of cavitation erosion can reduce the lifetime of the components of hydraulic machines. In this article, we present a new numerical approach to predict the mechanical impact resulting from the implosion of a cloud of bubbles, based on an energy approach. The objective of this approach is to determine the main damage mechanisms and to estimate the intensity of the impact pressure near the surface. The large eddy simulation (LES) approach is coupled with a homogeneous cavitation model to assess the risk of erosion around the hydrofoil NACA0009. Indeed, three functions, namely the Pressure Intensity Function (PIF), the steam intensity function and the Erosive Power Function (EPF), are applied to assess the spatial distribution of eroded areas. The calculations show that the functions based on the pressure term are in good agreement with the experiments, namely: the PIF and EPF functions. On the other hand, we assume that the implosion of the cloud of bubbles produces a pressure wave, which in turn causes the implosion of small bubbles near the wall. Then the erosion will be the result of these secondary implosions and not of the cloud of bubbles. Therefore, we vary the degree of proximity of these micro-bubbles near the wall to choose either the shock wave or the micro-jet to extrapolate the pressure field. We can compare these estimates with the existing erosion measurements and we can conclude that the calculations respond more to the probability of the presence of a micro-jet than to the presence of a shock wave.

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Section: Introductionmentioning

confidence: 99%

Numerical Prediction Approach of Cavitation Erosion based on 3D Simulation Flow

2022

JAFM

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“…The cavitation refers to the phenomenon of vaporization and condensation caused by variations in the local pressure in the liquid [1][2][3][4] . Most of the hydraulic machinery, such as the pumps, the turbines and the ship propellers, operates at a high speed [5] .…”

Section: Introduction mentioning

confidence: 99%

Numerical assessment of the erosion risk for cavitating twisted hydrofoil by three methods

Lei

Cheng

et al. 2021

J Hydrodyn

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In this paper, the large eddy simulation (LES) method in conjunction with the Zwart cavitation model is adopted for the assessment of the erosion risk on a hydrofoil surface. The numerical results are in good agreement with the experiments. On this basis, three methods, namely the intensity function method (IFM), the time-averaged aggressiveness indicators (TAIs) and the gray level method (GLM), are applied for the assessment of the erosion risk. It is shown that the erosion intensity index of the IFM is extremely sensitive to the artificially selected thresholds, which greatly limits the application of the method. The erosion risk predicted by four indicators in the TAIs does not agree well with the experimental results. Further analysis demonstrates that the GLM using the instantaneous pressure field is relatively satisfactory, which can provide a reasonable assessment of the erosion and is not very sensitive to the artificially selected thresholds. To further improve the accuracy of the GLM for the erosion risk prediction, the time-average pressure field is adopted in the GLM for the erosion evaluation. It is suggested that the erosion assessment by using the time-averaged pressure field is in better agreement with the experimental results when compared with that by using the instantaneous pressure field.

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