Particle‐laden liquid jet impingement on a moving substrate

Rahmani, Hatef; Green, Sheldon

doi:10.1002/aic.15800

Cited by 4 publications

(4 citation statements)

References 25 publications

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“…Liquid properties at 25°C ambient temperature were as follows 22 : density 1315 kg/m 3 , viscosity 105 mPa s and surface tension 73.3 mN/m. The working medium was purposefully selected to have a relatively high viscosity in order to minimise the slippage of liquid against the cylinder surface, 21 and to ensure laminar flow in the free‐jet and impingement zone that is preferable for splash‐free deposition process 23 …”

Section: Methodsmentioning

confidence: 99%

Free surface lubrication of rotating cylinders by impacting Newtonian liquid jet

Bizjan

Širok

Blagojevič

2021

Lubrication Science

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Free surface lubrication of rotating cylinders by Newtonian liquid jets was investigated at different impingement positions, jet‐ and circumferential velocities. The interaction between impinging round laminar jet and rotating surface was characterised by high‐speed imaging. Compared to flat surface impingement, the liquid deposition mechanism is more complex and often accompanied by phenomena such as splashing, jet deflection and formation of radial surface stripes. Liquid splashing initially develops in direct deposition regime due to hydraulic jump‐induced droplet shedding, transitioning to lamella instability splash at higher Reynolds numbers. The critical Reynolds number for splash onset is of same order of magnitude as for flat surface impingement and fairly constant at low relative jet impingement angles, but increases exponentially when angle approaches 90°. Liquid film width and thickness were both determined proportional to the square root of the jet/surface velocity ratio, with respective power law models in good agreement with measured values.

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Section: Methodsmentioning

confidence: 99%

Free surface lubrication of rotating cylinders by impacting Newtonian liquid jet

Bizjan

Širok

Blagojevič

2021

Lubrication Science

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“…In rail transport, which primarily motivated this work, a pool of 'liquid friction modifier', a viscous liquid containing small amounts of microscopic solid lubricants like graphite, is deposited on the track ahead of the approaching train. Some of this liquid is picked up by the passing wheel and can reduce wheel and rail wear, noise and fuel consumption (Harmon & Lewis 2016;Stock et al 2016;Rahmani & Green 2017). When the approaching wheel contacts this liquid pool, the lubrication pressure developed can be sufficient to raise the wheel slightly off the track.…”

Section: Introductionmentioning

confidence: 99%

“…Some of this liquid is picked up by the passing wheel and can reduce wheel and rail wear, noise and fuel consumption (Harmon & Lewis 2016; Stock et al. 2016; Rahmani & Green 2017). When the approaching wheel contacts this liquid pool, the lubrication pressure developed can be sufficient to raise the wheel slightly off the track.…”

Section: Introductionmentioning

confidence: 99%

Lubricated rolling over a pool

et al. 2022

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Experiments are conducted to explore the rolling of a cylinder over a pool of viscous fluid. The speed, width and loading of the cylinder are varied along with the initial depth and length of the viscous pool. Depending on the conditions, the cylinder will either ride on a lubrication film or remain in solid contact with the underlying substrate. For the former situation, a lubrication theory is presented that describes the pressure underneath the cylinder and the thickness of the film. The theory approximates the flow by the one-dimensional Reynolds equation with the addition of one term, with an adjustable parameter, to account for the flux of fluid to the cylinder sides. Once this parameter is calibrated against experiment, the theory predicts peak lubrication pressures, gap sizes and film thicknesses to within approximately ten per cent. For lubricated rolling, the film splits evenly between the cylinder and substrate downstream of the nip. The printer's instability arises during the splitting process, patterning the residual fluid films on the substrate and cylinder. If the pool length is less than the cylinder circumference, the fluid adhering to the cylinder is rotated back into contact with the substrate, and when there is sufficient adhered fluid a lubrication film forms that can again be modelled by the theory. Conversely, if there is insufficient adhered fluid, no contiguous lubrication film is formed; instead, the pattern from the printer's instability ‘prints’ from the cylinder to the substrate.

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“…Top-of-rail friction control through application of liquid friction modifiers (LFM) is widely implemented in heavy haul freight railways. 1,2 LFMs change the coefficient of friction between the wheel and rail to a value less than that of pure metal-to-metal contact, but are still sufficiently high to not compromise traction and braking. This reduced level of friction significantly reduces wear, curve noise, and the lateral force at the wheel-rail interface in a curve.…”

Section: Introductionmentioning

confidence: 99%

Carrydown of liquid friction modifier

Rahmani

Gutsulyak

Stanlake

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part F:

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A small-scale laboratory apparatus was built to study liquid friction modifier (LFM) behavior in a top-of-rail application. A field experiment was also carried out to complement the laboratory findings. KELTRACK® (a water-based LFM) was used as the test fluid. Laser-induced fluorescence served to measure the LFM thickness left on the track after the passage of the wheel. The lab experiments show that the LFM cannot withstand the high wheel-rail contact pressure in the nip present in cargo rail situations. As a result, the liquid is squeezed out laterally and attaches to the edges of the wheel contact band. This “edge liquid” is then carried down the track on the wheel. Gravimetric measurements of the wheel contact band confirm this observation, and show that only a minute amount of liquid is carried through the nip in the valleys between surface roughness features. In the field experiment, the LFM is applied from a trackside unit on a tangent section of the track. About 500 m downstream of the application point, the track has a curved section. LFM cannot be detected anywhere on the track a short distance (∼200 m) past the application unit. However, LFM is detectable on the curved sections of the track up to approximately 2 km from the application unit. This LFM on the curved track is believed to be due to transfer of the “edge liquid” from the wheel to the track, caused by the movement of the contact band as the train rounds a curve. The presence of LFM on the curved track far downstream is consistent with prior measurements of reduced lateral force on the curved track downstream of LFM application sites.

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Particle‐laden liquid jet impingement on a moving substrate

Cited by 4 publications

References 25 publications

Free surface lubrication of rotating cylinders by impacting Newtonian liquid jet

Free surface lubrication of rotating cylinders by impacting Newtonian liquid jet

Lubricated rolling over a pool

Carrydown of liquid friction modifier

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