Analysis of the air-water-sediment flow behavior in Pelton buckets using a Eulerian-Lagrangian approach

Guo, Benhai; Xiao, Yexiang; Kumar, Anant; Liang, Quanwei; Liu, Jie

doi:10.1016/j.energy.2020.119522

Cited by 25 publications

(25 citation statements)

References 30 publications

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“…It is pointed out in the literature that the particle separation velocity and separation angle depend on the bucket curvature, and the curvature of the blade and cavitation also affect the particle separation velocity and separation angle. 17 According to the previous analysis, the free surface vortex will not directly denude the impeller structure. The main reason is that the air-entrainment by FSV changes the particle position, particle local velocity and particle concentration.…”

Section: Discussionmentioning

confidence: 98%

“…Thus, the sediment content in the water flow is diluted before reaching the unit. 17 This diluted and dispersed flow allows some simplification in the numerical method, in this section, the mathematical models involved in the calculation model will be described in detail, including multiphase flow model, turbulence model, meshing strategy, boundary conditions and calculation parameters.…”

Section: Mathematical Methodsmentioning

confidence: 99%

“…According to the method combining VOF model and Lagrange model used to explore the erosion characteristics in the bucket, 17 the heat exchange between fluids is not considered, there is no mass exchange between water, air and sand. The fluid motion pattern can be described as two parts: ①the apparent interface of water and air phases exists in the vortex, ②the solid particles are dispersed in the water.…”

Section: Multiphase Flow Modelmentioning

confidence: 99%

“…16 Guo Bao proposed a method combining VOF model and Lagrange model to explore the erosion characteristics in the bucket. 17,18 The existence of vortex will change the stability of flow field and the movement of particles in the pump, but so far, there is no research on the influence of sand-laden free surface vortex on the erosion in the pump.…”

Section: Introductionmentioning

confidence: 99%

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Numerical prediction of the effect of free surface vortex air-entrainment on sediment erosion in a pump

Song

Wang

2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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Sediment erosion through synergetic effects between free surface vortex (FSV) and particle erosion in silt-laden flow seriously affects the safe operations of pump. The purpose of this paper is to study the influence of free surface vortex entrainment on the erosion inner the pump impeller, aimed at the FSV and sediment erosion in sediment laden flow in a pump station of Yellow River, a new Eulerian-Lagrange approach was applied to simulate the sediment-laden flow by combining the Lagrange particle tracking approach and Volume of Fluid (VOF) method, followed by the application of Tabakoff model to estimate the erosion. Volume of fluid method was used to simulate the continuous flow FSV, and Lagrange method the particle trajectory. The theoretical model and filed results on site were used to verify the reliability of the proposed approach. Free surface vortex on particle motion and microscopic interactions between air and erosion were reviewed and discussed. Combined with the theoretical analysis and calculation results, the particle impact angle in the impeller was analyzed, and the erosion types were defined. Air entrainment by FSV does not directly erode the impeller components, but mainly changes the position, the local velocity and the concentration of the particles, which aggravates the sediment erosion in the impeller. Interestingly, air entrainment can reduce the surface erosion at some instantaneous moments. The present work may provide important engineering insights to resolve the erosion.

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Section: Discussionmentioning

confidence: 98%

Section: Mathematical Methodsmentioning

confidence: 99%

Section: Multiphase Flow Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Numerical prediction of the effect of free surface vortex air-entrainment on sediment erosion in a pump

Song

Wang

2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…Increasing jet velocity also accentuated erosion on the injector spear [27]. Jet velocity and bucket geometry influenced sediment erosion on Pelton runners [28].…”

Section: Introductionmentioning

confidence: 96%

Numerical Investigation of Nozzle Jet Flow in a Pelton Microturbine

2021

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The characterization of flow through Pelton hydro turbines allows the optimization of their operation and maximization of energy performance. The flow in the injector of Pelton turbines and in the free jet area (the area from the injector outlet surface to the runner bucket inlet surface) is influenced by several parameters: the geometry of injector components (nozzle and injector spear), the injector opening, and the turbine head. The parameters of the free jet flow (velocity distribution, pressure distribution, and jet spread) are reflected in the turbine efficiency. The research presented in this paper focuses on the numerical characterization of flow in the injector and the free jet of a Pelton microturbine. Three injector geometries were considered, with different nozzle diameters: 13.3 mm, 14.4 mm, and 16.3 mm. For each of these geometries, the flow was analyzed for five values of turbine head (H = 15 m, H = 20 m, H = 25 m, H = 30 m, H = 35 m) and six values of injector opening (S = 3 mm, S = 6 mm, S = 9 mm, S = 12 mm, S = 15 mm, S = 18 mm). The results of numerical simulations were used to plot injector flow-rate characteristics and injector force characteristics (the resultant force on the injector spear and the resultant force on the injector nozzle). The highest influence on the flow rate variation is given by the variation of turbine head, followed by the variation of the injector opening and the variation of the nozzle diameter. Increasing the nozzle diameter accentuates the variation of the flow rate versus the turbine head. The variation of axial velocity and pressure in the free jet is presented for four sections parallel to the outlet section of the injector. The injector openings that generate the highest values of velocity/pressure on the runner inlet surface are highlighted. The results allow optimization of functional parameters for increasing turbine efficiency and optimizing the design process of Pelton microturbines.

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