Flow Characteristics of a Powder Lubricant Sheared Between Parallel Plates

Zhou, Lei; Khonsari, M. M.

doi:10.1115/1.555337

Cited by 36 publications

(28 citation statements)

References 16 publications

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“…Khonsari [57] who performed a similar parametric e p study on a granular shear flow using a continuum modeling approach. , which are all set to 0.8.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Three-dimensional physics-based cellular automata model for granular shear flow

Marinack

Higgs

2015

Powder Technology

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Granular flows continue to be a complex problem in nature and industry where solid particles exhibit solid, liquid, and gaseous behavior in a manner which is often difficult to predict both locally and globally. In solids processing applications such as pharmaceutical production, food processing, and coal processing, the ability to accurately predict particle flows can improve process efficiency and product effectiveness. The "gold standard" for the modeling and prediction of granular flows is the discrete element method (DEM), which provides a rigorous physical treatment of particle interactions. One possible supplement to DEM-based analysis is lattice-based cellular automata (CA). CA provides a platform for obtaining fast predictions by pairing rule-based mathematics with high-fidelity physics to rapidly model physical processes, such as granular flows. The present work develops a novel three-dimensional (3D) physics-based CA framework for modeling granular shear flows. This 3D CA model extends the framework's modeling capabilities beyond the granular kinetic regime, includes treatments for force chains, and provides reasonably high accuracy in terms of predicting fundamental granular flow experiments. The predictive capabilities and quantitative accuracy of this CA model have been tested and validated against experimental shear flow results from an annular shear cell. Results from this validation work suggest that the model accurately predicts local flow properties. A parametric study varying the particle-particle coefficient of restitution demonstrated the ability of A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 the 3D CA model to capture nonlinear trends in the local solid fraction profiles. A time study was also performed to highlight the computational efficiency of the 3D CA framework developed in this work. Results of this study showed that even at relatively low particle counts (10 4 ), the 3D CA model provides for considerable computational savings, with run times of two orders of magnitude less than a 2D DEM model.

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“…Khonsari [57] who performed a similar parametric e p study on a granular shear flow using a continuum modeling approach. , which are all set to 0.8.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Three-dimensional physics-based cellular automata model for granular shear flow

Marinack

Higgs

2015

Powder Technology

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“…They compared their new CA model to the GKL continuum model for granular flows in a parallel shear cell. Others have also introduced new granular flow models and studied various characteristics of granular flows in parallel shear cells [13][14][15][16]. Additional studies have been conducted using a molecular dynamics (MD) approach to study a steady-state, gravity-free Couette flow of inelastic hard spheres with rough walls [15,16].…”

Section: Introductionmentioning

confidence: 98%

Utilizing the Explicit Finite Element Method for Studying Granular Flows

2007

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Granular flows are systems of complex dry particulates whose behavior is difficult to predict during sliding contact. Existing computational tools used to simulate granular flows are particle dynamics, cellular automata (CA), and continuum modeling. In the present investigation, another numerical tool-the explicit finite element method (FEM)-is analyzed as a potential technique for simulating granular flow. For this purpose, explicit dynamic finite element models of parallel shear cells were developed. These models contained 52 particles and consisted of granules that are both round and multishaped (diamond, triangle, and rectangle). Each parallel shear cell consisted of a smooth stationary top wall and a rough bottom surface that was given a prescribed velocity of U = 0.7 in/sec (1.78 cm/s). The coefficient of friction (COF) between the particle-particle and particle-wall collisions was varied between 0.0 and 0.75. Utilizing the output of the simulations, results are presented for the shear behavior, particle kinetic energy, and particle stresses within the shear cell as a function of time. As a means of validating the explicit technique for granular flow, a 75 particle, zero roughness, couette shear cell model (solid fraction of 0.50) is subsequently presented for which direct comparisons are made to the results published by Lun. [Lun, C.K. et al.: Phys. Fluids 8, 2868-2883(1996] Overall, the results indicate that the explicit FEM is a powerful tool for simulating granular flow phenomena in sliding contacts. In fact, the explicit method demonstrated several advantages over existing numerical techniques while providing equivalent accuracy to the molecular dynamics (MD) approach. These advantages included being able to monitor the collision (sub-surface and surface) stresses and kinetic energies of individual particles over time, the ability to analyze any particle shape, and the ability to capture force chains during granular flow.

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“…Heshmat's measurements reveal about ''powder pressure'' in the clearance space of a sliding bearing with very similar features to that of a liquid lubricated bearing. An improvement of sliding bearing performance with solid lubricant powders using Heshmat [2] quasi-hydrodynamic approach and Khonsary et al [5][6][7] theory of granular lubrication is still lacking in literature, in particular, for the high temperature conditions. the determination of influence of surface modification of high temperature sliding bearings with solid lubricant nanoparticles on the friction and wear properties of the is shown to be very important, and it is the main goal of this paper, which is continuation of analysis shown in [3].…”

Section: Introductionmentioning

confidence: 99%

Surface Modification Of The High Temperature Porous Sliding Bearings With Solid Lubricant Nanoparticles

Wiśniewska-Weinert¹

2015

Archives of Metallurgy and Materials

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A surface modification of stainless steel bearing sleeves is developed to improve the tribology characteristics at high temperature. Solid lubricant nano-and microparticles are applied for this purpose. To create the quasi-hydrodynamic lubrication regimes, the solid lubricant powder layer is made by developed pressure impregnation technique. Porous sliding bearing sleeve prototypes were made by powder metallurgy technique. The purpose of the paper is to define the friction and wear characteristics of the sleeves and to determine the influence of sealing of the sliding interface on these characteristics. It is found that application of WS 2 sold lubricant nano-and micro-particles and preservation of a particle leakage out of interface allows to achieve at the high temperature the friction coefficients comparable to those at ambient temperature.Keywords: bearing sleeves, solid lubricant, powder layer, powder metallurgy, nano-and micro-particles Opracowano modyfikację powierzchni bieżni łożysk wykonanych ze stali nierdzewnej w celu poprawy charakterystyki tribologicznej w podwyższonej temperaturze poprzez zastosowanie stałego czynnika smarnego w postaci nano-i mikro-cząstek. W celu wytworzenia warunków kwasi-hydrodynamicznego smarowania, wytworzono warstwę z proszku smarnego na drodze infiltracji ciśnieniowej. Celem pracy było wyznaczenie charakterystyki ściernej i zużyciowej bieżni oraz określenie wpływu uszczelnienia ślizgających się powierzchni na te charakterystyki. Stwierdzono, że zastosowanie WS 2 jako stałego smaru w postaci nano-i mikro-cząstek oraz zabezpieczenie wypływu z granicy fazowej pozwala uzyskać wartość współczynnika tarcia porówny-walną z otrzymywaną dla temperatury otoczenia.

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Flow Characteristics of a Powder Lubricant Sheared Between Parallel Plates

Cited by 36 publications

References 16 publications

Three-dimensional physics-based cellular automata model for granular shear flow

Three-dimensional physics-based cellular automata model for granular shear flow

Utilizing the Explicit Finite Element Method for Studying Granular Flows

Surface Modification Of The High Temperature Porous Sliding Bearings With Solid Lubricant Nanoparticles

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