Publication

FVPM numerical simulation of the effect of particle shape and elasticity on impact erosion

Résumé

The erosion of hydraulic machines by solid particle impacts is a widespread problem that leads to outage for expensive repairs, efficiency reduction, and cavitation enhancement. Numerical simulations can be used to study the phenomenon, provided they feature accurate thermomechanical and contact modeling. Numerical investigations often assume that the impacting particles are spherical and rigid, with only some recent studies modeling them as elastic polyhedrons or spheres. However, in the specific case of the erosion of hydraulic machines, particles are far from spherical or polyhedral and are less rigid than the base material. The present investigation focuses on the effect of the particle shape and elasticity on the erosion of oxygen-free copper and martensitic stainless steel 13Cr-4Ni impacted by quartz sediments. First, a novel algorithm to generate realistically-shaped sediment discretizations is presented, bypassing the need to use simplified shapes such as polyhedrons. The algorithm is shown to produce particle discretizations of predefined characteristic size that closely follow the objective sphericity value selected, which can cover the full range of sphericity values found in real sediments. Then, the effect of the particle elasticity on the impact damage is investigated, revealing that an error of up to 38 % is introduced by assuming that the particles are rigid. The effect of the particle shape is then assessed. For the case of copper, sharp sediments generate an increase in damage per unit mass of up to 225 % with respect to spherical particles; a comparable effect is expected on the erosion rate. For the martensitic stainless steel, the shape effect is similar in character but significantly weaker in magnitude. The results are analyzed and explained in terms of the known erosion mechanisms and their dependence on the particle shape, the material ductility and hardness.

À propos de ce résultat
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.
Concepts associés (35)
Érosion
thumb|Effet de la combinaison de l'érosion éolienne et hydrique (Coyote Buttes, Vermilion Cliffs National Monument, États-Unis). thumb|Risque d'érosion des sols (Europe méditerranéenne). En géomorphologie, l’érosion est le processus de dégradation et de transformation du relief, et donc des sols, roches, berges et littoraux qui est causé par tout agent externe (donc autre que la tectonique). Un relief dont le modelé s'explique principalement par l'érosion est dit « relief d'érosion ».
Sediment transport
Sediment transport is the movement of solid particles (sediment), typically due to a combination of gravity acting on the sediment, and the movement of the fluid in which the sediment is entrained. Sediment transport occurs in natural systems where the particles are clastic rocks (sand, gravel, boulders, etc.), mud, or clay; the fluid is air, water, or ice; and the force of gravity acts to move the particles along the sloping surface on which they are resting.
Érosion des sols
vignette|redresse=1.7|Cartographie mondiale de la vulnérabilité des sols à l'érosion hydrique. Des taux d'érosion deux fois plus élevé que le taux de formation des sols (voire quarante fois dans les pays développés actuels dont l'agriculture productiviste se traduit par un labour ou un travail du sol intensif) explique l'espérance de vie des grandes civilisations antiques rythmés par la loi des cycles millénaires avec une phase d'expansion suivie d'une phase de déclin (en moyenne de 800 à , donnée compatible avec l'érosion complète des couches arables et fertiles par leur culture intensive reposant sur environ un mètre de terre végétale).
Afficher plus
Publications associées (47)

Copper Complexes with Diazoolefin Ligands and their Photochemical Conversion into Alkenylidene Complexes

Rosario Scopelliti, Kay Severin, Farzaneh Fadaei Tirani, Bastiaan Kooij, Paul Varava

Homometallic copper complexes with alkenylidene ligands are discussed as intermediates in catalysis but the isolation of such complexes has remained elusive. Herein, we report the structural characterization of copper complexes with bridging and terminal a ...
2022

Present-day sediment dynamics and provenance of the Gornergletscher

François Mettra, Bruno Belotti, Fien De Doncker

Glacial erosion processes shape the Earth’s surface. Nevertheless, the processes that drive glacial erosion and the subsequent export of sediments are poorly understood and quantified. These processes include ice sliding, which controls erosion by abrasion ...
2021

Multiscale simulation of erosive wear in a prototype-scale Pelton runner

François Avellan, Ebrahim Jahanbakhsh, Sebastián Camilo Leguizamón Sarmiento, Siamak Alimirzazadeh

The technical capacity to predict the erosion process is instrumental for the optimization of the runner designs and operation strategies of hydroelectric plants. A multiscale model of erosion recently formulated by the authors and validated on a laborator ...
2020
Afficher plus
MOOCs associés (10)
Plasma Physics: Introduction
Learn the basics of plasma, one of the fundamental states of matter, and the different types of models used to describe it, including fluid and kinetic.
Plasma Physics: Introduction
Learn the basics of plasma, one of the fundamental states of matter, and the different types of models used to describe it, including fluid and kinetic.
Plasma Physics: Applications
Learn about plasma applications from nuclear fusion powering the sun, to making integrated circuits, to generating electricity.
Afficher plus