A New Method to Visualize Grease Flow in a Double Restriction Seal Using Microparticle Image Velocimetry

Green, T.M.; Baart, Pieter; Westenberg, L.G.; Lundström, T. Staffan; Höglund, Erik; Lugt, Piet M.; Li, J.X.

doi:10.1080/10402004.2011.604759

Cited by 20 publications

(14 citation statements)

References 9 publications

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“…Radulescu et al [24] investigated the flow in pipes with discontinuities, which also could be applied to the flow in bearings. This work is a continuation of previous studies of the flow in closed straight channels [29,17] and in a 3D double restriction seal geometry [14,1,18]. A channel with a 90 • elbow is used and an analytical model of the flow is developed and combined with experimental data from micro Particle Image Velocimetry (µPIV) measurements of the flow in the elbow.…”

Section: Introductionmentioning

confidence: 97%

Grease flow in an elbow channel

Westerberg

Farré-Lladós

et al. 2015

Tribol Lett

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Lubricating greases are materials characterized by a complex nonNewtonian rheology. This study is a continuation of previous studies on the coupling between grease rheology and grease flow in a straight channel-and concentric cylinder geometry. The problem has been modeled and validated with experiments. Here the flow in an elbow channel introducing a non-symmetric distribution of shear stress throughout the cross section of the channel elbow, as well as varying shear rates through the transition from the channel inlet to the outlet. The flow has been modeled both for higher flow rates and for creep flow. The influence of the grease rheology and flow conditions to wall slip, shear banding and an observed stick-slip type of motion observed for low flow rates are presented. The effect on the flow of the applied pressure is also investigated showing that the flow is sensitive to the pressure in the angular (ϕ) direction of the elbow. For high flow rates it is shown that flow separation occur with a resulting circulation in the elbow.

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Section: Introductionmentioning

confidence: 97%

Grease flow in an elbow channel

Westerberg

Farré-Lladós

et al. 2015

Tribol Lett

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“…Consequently, the life of the rollers is shortened as a result of, among other things, their easier contamination in the dust-laden environment. Using microparticle image velocimetry (lPIV), wall effects were observed also during the shearing of grease in the clearances of axial and radial labyrinth seals [15,16]. There are also research works indicating that wall effects in greases affect the effectiveness of the lubrication of slide bearings.…”

Section: Introductionmentioning

confidence: 99%

Studies of the Influence of Temperature and the Energy State of the Surface Layer of Adsorbents on Wall Effects in Soap-Based Greases

2016

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This paper presents the results of studies of wall effects in commercial soap-based greases LT4-S2 and HUTPLEX EP-2, thickened with, respectively, lithium 12-hydroxystearate and overbased calcium sulfonate. The studies were conducted in the presence of five different materials: copper alloy C11000, bronze B476, EPDM rubber and PTFE and PU thermoplastics. The influence of the energy state of the surface layer of the adsorbents and temperature (ranging from -20 to 60°C) on the intensity of wall effects was investigated. Changes in the structural viscosity and shear stress in the boundary layer area in the greases and the soap-based thickener's ability to adsorb on the surfaces of the adsorbents were determined by evaluating the rheological parameter plateau modulus.

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“…Baart et al [11] has used µPIV to measure the velocity profile across the grease pocket at a given plane set by the focal plane of the microscope. µPIV is a non-intrusive method that uses a high-speed camera connected to a microscope, and synchronized/triggered by a computer, to take images of a particle seeded (grease) flow; see, e.g., Green et al [12] for further details. Through a correlation algorithm, the particle motion is tracked, and the velocity vectors in the geometry are obtained.…”

Section: Particle Migration Model By Baart Et Al [11]mentioning

confidence: 99%

“…Baart et al [11] investigated the motion of contaminant particles in a grease pocket in a double restriction seal geometry developed by Green et al [12]; see Figure 1. Baart et al [11] used the analytical velocity model developed by Batchelor [13] for the flow in a wide pocket where the velocity is solely linear and one-dimensional.…”

Section: Introductionmentioning

confidence: 99%

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Contaminant Particle Motion in Lubricating Grease Flow: A Computational Fluid Dynamics Approach

et al. 2018

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Abstract:In this paper, numerical simulations of particle migration in lubricating grease flow are presented. The rheology of three lithium greases with NLGI (National Lubricating Grease Institute) grades 00, 1 and 2 respectively are considered. The grease is modeled as a single-phase Herschel-Bulkley fluid, and the particle migration has been considered in two different grease pockets formed between two concentric cylinders where the inner cylinder is rotating and driving the flow. In the wide grease pocket, the width of the gap is much smaller compared to the axial length scale, enabling a one-dimensional flow. In the narrow pocket, the axial and radial length is of the same order, yielding a three-dimensional flow. It was found that the change in flow characteristics due to the influence of the pocket lateral boundaries when going from the wide to the narrow pocket leads to a significantly shorter migration time. Comparing the results with an existing migration model treating the radial component contribution, it was concluded that a solution to the flow in the whole domain is needed together with a higher order numerical scheme to obtain a full solution to the particle migration. This result is more pronounced in the narrow pocket due to gradients in the flow induced by the lateral boundaries.

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A New Method to Visualize Grease Flow in a Double Restriction Seal Using Microparticle Image Velocimetry

Cited by 20 publications

References 9 publications

Grease flow in an elbow channel

Grease flow in an elbow channel

Studies of the Influence of Temperature and the Energy State of the Surface Layer of Adsorbents on Wall Effects in Soap-Based Greases

Contaminant Particle Motion in Lubricating Grease Flow: A Computational Fluid Dynamics Approach

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