Research on synergistic erosion by cavitation and sediment: A review

Abstract

Sediment erosion frequently occurs in areas with high incidences of cavitation. The collaborative impact of abrasion and cavitation presents a host of challenges, threats, and damages to hydraulic engineering. However, little is known about the synergistic wear mechanism, and research conclusions remain inconsistent. In this work, relevant studies on synergistic erosion have been collected, classified, and analyzed. Presently, research on synergistic wear primarily operates at the macro and micro levels. The microscopic level enables the visualization and quantification of the process by which particles gain momentum from bubbles, the trajectory of particle acceleration, and the mechanism that triggers strong interactions between bubble-particle. At the macro level, erosion is understood as the summation of damage effects on the wall that is caused by the interaction between a plethora of bubbles of varying scales and numerous particles. The synergistic bubble-particle effect is reflected in the dual inhibiting or promoting mechanism. Furthermore, while numerical simulations could be realized by coupling cavitation, multiphase flow, and erosion models, their accuracy is not infallible. In the future, the dual role of particles, and particles driven by micro-jets or shock waves should be fully considered when establishing a combined erosion model. In addition, enhancing the influence of flow field and boundary parameters around bubbles and utilizing FSI would improve the predictive accuracy of erosion location and erosion rate. This work helps to elucidate the combined wear mechanism of hydraulic machinery components in sediment-laden flow environments and provides a theoretical basis for the design, manufacture, processing, and maintenance of hydraulic machinery.

Keywords: Cavitation damage; Dual mechanism; Numerical techniques; Particle erosion; Synergistic effect.

Fig. 1

Global percentage of undeveloped hydropower and annual sediment load deposition (Figures are recreated from ref. [35]).

Fig. 2

Illustration of cavitation effect and particle .

Fig. 3

Wear zones of the Chenani Hydro-Power Plant spray needle .

Fig. 4

Erosion due to sand particles and cavitation (left Puwakhola HPS) and erosion due to cavitation (right Kulekhani HPS) in the bucket .

Fig. 5

Wear on the Francis turbine at the Amaime hydropower plant after six months of operation .

Fig. 6

Abrasion photo of runner blade of Muzhati III power station in Aksubai, Xinjiang .

Fig. 7

Wear of the front shroud and pump casing of a pump station in Shanghai .

Fig. 8

Three stages of bubble development on particles .

Fig. 9

Multiple starting points of cavitation on the particle .

Fig. 10

Particle arrangement relative to the electrode in the test .

Fig. 11

Position of bubble and glass particle at different moments .

Fig. 12

Process of the collapsing bubble pushing the particles .

Fig. 13

Motion of particles during bubble evolution .

Fig. 14

Effect of particles on the evolutionary morphology of cavitation bubbles. (a) Without particles. (b) The bubble collapses and interacts with a large particle. (c) The bubble collapses and interacts with eight small particles. .

Fig. 15

Deformation of the surrounding particles caused by single bubble collapse .

Fig. 16

Two acceleration mechanisms of particles .

Fig. 17

Acceleration mechanism of particles by micro-jet and shock wave .

Fig. 18

Particle acceleration mechanism illustration .

Fig. 19

Curves of mass loss with exposure time, particle size, and concentration .

Fig. 20

Wear mechanism of cavitation alone and synergistic effect at different sediment concentrations .

Fig. 21

Comparison of theoretical and experimental values .

Fig. 22

Comparison between simulation results and experimental records (The contours of the particle and bubble obtained by simulation are represented by solid gray lines and dashed white lines, respectively) .

Fig. 23

Comparison between experimental and model .

Fig. 24

Diagram of a bubble-particle system and volume element of particle suspension .

Fig. 25

Comparison between the image sequence obtained by experiment and the bubble interface obtained by CFD simulation .

Fig. 26

Bubble-particle interaction process .

Fig. 27

Pressure field under different bubble size ratios shows the propagation of bubble emission shock wave at different times .

Fig. 28

Particle trajectory and cavity structure in Venturi tube .

Fig. 29

Sand volume fraction on the surface of the rotating disk under different conditions .