Evaluation of cavitation-induced pressure loads applied to material surfaces by finite-element-assisted pit analysis and numerical investigation of the elasto-plastic deformation of metallic materials

Pöhl, Fabian; Mottyll, Stephan; Skoda, Romuald; Huth, S.

doi:10.1016/j.wear.2014.12.048

Cited by 62 publications

(32 citation statements)

References 37 publications

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“…Extensions of BEM involve Euler/Navier-Stokes flow solvers, which may include compressibility effects as well and sharp interface/ interface capturing/tracking techniques [55]. More recent work employs multiphase flow techniques for handling of the gas/liquid interface [56,57] using a Homogeneous Equilibrium Model. Apart from single fluid approaches, various interface tracking methodologies have been employed for the prediction of pressure due to bubble collapse.…”

Section: Models Suitable For Single-bubbles (Microscales)mentioning

confidence: 99%

“…This method differs from VOF or LS, in the sense that the interface is explicitly tracked by a set of Lagrangian marker points that define the interface topology, enabling high fidelity simulations and predictions to be made, without smearing of the interface. Assessing current methodologies, the treatment of the vapour/gas and liquid mixture, both Homogeneous Equilibrium [57] or non-equilibrium interface tracking immiscible fluid methodologies are applicable. While both methodologies have been successfully employed for studying the pressure field generated on the wall due to the collapse of nearby bubbles for various configurations, the methodology of interface capturing is definitely less restricting, allowing one to simulate gaseous/vaporous mixtures within the bubble, while also prescribing finite rate of mass transfer and giving the opportunity of imposing surface tension, which is important in the case of bubble nucleation.…”

Section: Models Suitable For Single-bubbles (Microscales)mentioning

confidence: 99%

“…In the literature, however, it is commonly assumed that liquids behave according to the stiffened gas EoS and the gas/vapour as an ideal gas [58,93,94] despite the strong evidence that the stiffened gas EoS may not be adequate, since it cannot replicate at the same time both the correct density and the speed of sound of the liquid [95]. For this reason, many researchers have recently turned towards more accurate relationships for describing the materials involved [57] and [96] developed by the authors. Such accurate EoS have been formulated by NASA [97,98] or in other investigations [99].…”

Section: Thermodynamic Closurementioning

confidence: 99%

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Modelling cavitation during drop impact on solid surfaces

Kyriazis

Koukouvinis

Gavaises

2018

Advances in Colloid and Interface Science

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The impact of liquid droplets on solid surfaces at conditions inducing cavitation inside their volume has rarely been addressed in the literature. A review is conducted on relevant studies, aiming to highlight the differences from non-cavitating impact cases. Focus is placed on the numerical models suitable for the simulation of droplet impact at such conditions. Further insight is given from the development of a purpose-built compressible two-phase flow solver that incorporates a phase-change model suitable for cavitation formation and collapse; thermodynamic closure is based on a barotropic Equation of State (EoS) representing the density and speed of sound of the co-existing liquid, gas and vapour phases as well as liquid-vapour mixture. To overcome the known problem of spurious oscillations occurring at the phase boundaries due to the rapid change in the acoustic impedance, a new hybrid numerical flux discretization scheme is proposed, based on approximate Riemann solvers; this is found to offer numerical stability and has allowed for simulations of cavitation formation during drop impact to be presented for the first time. Following a thorough justification of the validity of the model assumptions adopted for the cases of interest, numerical simulations are firstly compared against the Riemann problem, for which the exact solution has been derived for two materials with the same velocity and pressure fields. The model is validated against the single experimental data set available in the literature for a 2-D planar drop impact case. The results are found in good agreement against these data that depict the evolution of both the shock wave generated upon impact and the rarefaction waves, which are also captured reasonably well. Moreover, the location of cavitation formation inside the drop and the areas of possible erosion sites that may develop on the solid surface, are also well captured by the model. Following model validation, numerical experiments have examined the effect of impact conditions on the process, utilizing both planar and 2-D axisymmetric simulations. It is found that the absence of air between the drop and the wall at the initial configuration can generate cavitation regimes closer to the wall surface, which significantly increase the pressures induced on the solid wall surface, even for much lower impact velocities. A summary highlighting the open questions still remaining on the subject is given at the end.

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Section: Models Suitable For Single-bubbles (Microscales)mentioning

confidence: 99%

Section: Models Suitable For Single-bubbles (Microscales)mentioning

confidence: 99%

Section: Thermodynamic Closurementioning

confidence: 99%

See 1 more Smart Citation

Modelling cavitation during drop impact on solid surfaces

Kyriazis

Koukouvinis

Gavaises

2018

Advances in Colloid and Interface Science

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“…More recently, inverse techniques based on solid mechanics computations using the Finite Element Method (FEM) have been developed in order to assess the hydrodynamic loading conditions (typically in GPa) that would generate each pit identified in a pitting test [4,5]. Flow aggressiveness can then be characterized by the distribution in amplitude and size of the hydrodynamic impact loads due to bubble collapses.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation of the Erosive Potential of a Leading Edge Cavity

Carrat¹,

Patella²,

Franc³

2019

IJFMS

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This paper presents a joint experimental and numerical analysis of the erosive potential of an unsteady cavity that develops at the leading edge of a two-dimensional hydrofoil and periodically sheds vapour clouds. From an experimental viewpoint, the erosive potential was characterized by pressure pulse height spectra. The hydrofoil was equipped with eight pressure sensors made of PVDF piezoelectric film that allowed the measurement of flow aggressiveness at different locations along the hydrofoil chord. It was shown that the mean peak rate over a large number of cavity pulsations exhibits a maximum at a distance from the leading edge close to the maximum cavity length. Moreover, the increase in flow aggressiveness caused by an increase in flow velocity can be explained by an increase in both amplitude and frequency of impact loads. From a numerical viewpoint, the unsteady Reynolds averaged Navier-Stokes (RANS) equations were solved using a modified k-ε RNG turbulence model together with a homogeneous cavitation model within a two-dimensional approach. Flow aggressiveness was estimated from the Lagrangian derivative of the computed void fraction that allows identifying the regions of collapse of vapour structures. Three different critical regions from an erosive viewpoint were numerically identified. Apart from the region of collapse of the shed cloud (which was not instrumented in the present study), the computations showed a maximum of aggressiveness around the maximum cavity length as found experimentally. Another region of high aggressiveness closer to the leading edge and associated to the upward movement of the re-entrant jet was predicted by the present numerical model but not confirmed experimentally, which probably shows the limitation of a two-dimensional approach.

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“…The importance of analyzing the surface finish and possible deformations of material lies in the characterization of tool operation and the way the material surface is affected. This provides the roughness profile (Ra) and the definition of the areas where fatigue or stress are generated by the tool [21] [22].…”

Section: Introductionmentioning

confidence: 99%

Machining With Cutting Tool Coated With Monolayer Of HfN

2016

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In this study, AISI 1020 steel was machined by chip removal, in dry conditions, using ASSAB 17 tool bits with Hafnium Nitride (HfN) monolayer coating, deposited as a thin film via magnetron sputtering physical vapor deposition (PVD) technique, and uncoated tool bits, used as reference system. The surfaces of the machined steel were evaluated and characterized using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). The use of monolayer HfN coating on the tool bits was demonstrated to improve the surface finish of the workpiece and reduce cutting process time and cost.Keywords: Monolayer, Surface roughness, Machining, Cutting Tools, Hafnium Nitride. ResumenEn este trabajo, se realizó el mecanizado por arranque de viruta del acero AISI 1020, en condiciones de ausencia de lubricación; utilizando buriles de acero rápido ASSAB 17, con recubrimiento monocapa de Nitruro de Hafnio (HfN) depositados como película delgada, mediante la técnica de deposición física en fase vapor (PVD) magnetrón sputtering y con buriles sin recubrir, usados como sistemas de referencias. Posteriormente se evaluaron las superficies obtenidas en el acero mecanizado, caracterizándolas mediante microscopia de fuerza atómica (MFA) y microscopia electrónica de barrido (MEB). Se evidencio que el uso de recubrimientos monocapa de HfN sobre los buriles de acero rápido, mejoran el acabado superficial del material mecanizado, reduciendo los tiempos y costos del proceso de corte.

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Evaluation of cavitation-induced pressure loads applied to material surfaces by finite-element-assisted pit analysis and numerical investigation of the elasto-plastic deformation of metallic materials

Cited by 62 publications

References 37 publications

Modelling cavitation during drop impact on solid surfaces

Modelling cavitation during drop impact on solid surfaces

Experimental and Numerical Investigation of the Erosive Potential of a Leading Edge Cavity

Machining With Cutting Tool Coated With Monolayer Of HfN

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