An Analytical Approach for Prediction of Elastohydrodynamic Friction with Inlet Shear Heating and Starvation

Paouris, Leonidas I.; Rahmani, Ramin; Theodossiades, Stephanos; Rahnejat, Homer; Hunt, Gregory; Barton, William

doi:10.1007/s11249-016-0740-5

Cited by 24 publications

(31 citation statements)

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“…7a can also be used to test equations, based on theory originally developed by Carslaw and Jeagar [26] and Archard [46] that are commonly used in studies to calculate the oil film temperature, (e.g. see [27,47,48]…”

Section: Resultsmentioning

confidence: 99%

3D Measurements of Lubricant and Surface Temperatures Within an Elastohydrodynamic Contact

Reddyhoff

Dini

2017

Tribol Lett

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We present an infrared microscopy technique, capable of measuring the temperature of both the bounding surfaces and the oil film in an elastohydrodynamic contact. This technique can, for the first time, spatially resolve the oil film temperature in three dimensions. The contact is produced by loading a steel ball against a sapphire disc, and the film is viewed using an infrared microscope focussing through the disc. Two band pass filters are used to isolate the radiation from the oil film, and Planck's law is applied to data obtained at a known temperature as part of the calibration procedure. The proposed technique requires the emissivity of the oil film to be measured, which is acquired in situ and is shown to vary strongly as a function of thickness and temperature. The technique is validated under pure rolling conditions, when the temperature of the oil film is equal to the controlled lubricant reservoir temperature, and also compared to an equation commonly used to predict average film temperatures, confirming the value of the unknown constant. The technique is then used to gain insights into the thermal/rheological behaviour within a contact. This is important since the temperature of elastohydrodynamic contacts is critical in determining friction and hence the efficiency of machine components and this technique enables much needed validation and provides input data for CFD and numerical simulations.

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Section: Resultsmentioning

confidence: 99%

3D Measurements of Lubricant and Surface Temperatures Within an Elastohydrodynamic Contact

Reddyhoff

Dini

2017

Tribol Lett

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“…The latter is influenced by viscosity variation under high pressures. 35,36 The contours of lubricant temperature at mid-section of the major axis of the elliptical contact footprint, along its minor axis are also provided in the figure. These show the temperature variation in the lubricant, as well as the adjacent solid contacting surfaces; the equivalent ellipsoidal solid (Figure 2) and the semi-infinite elastic half space.…”

Section: Resultsmentioning

confidence: 99%

“…Recent rheological models are more suited for this purpose as highlighted by Habchi et al 35 and Paouris et al 36 However, the focus of this paper is on mixed non-Newtonian conditions. Lubricant density variation with pressure and temperature is given as…”

Section: The Non-newtonian Elastohydrodynamic Conjunctionmentioning

confidence: 99%

“…The model did not take into account the effect of asperity interactions. The same approach was also used by Paouris et al 36 for circular point contact of a sphere against a very smooth disc using a minitraction machine (MTM). Inlet lubricant starvation and shear heating were included in the model, which agreed well with the experimental measurements of generated friction.…”

Section: Introductionmentioning

confidence: 99%

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Non-Newtonian mixed thermo-elastohydrodynamics of hypoid gear pairs

Mohammadpour

Theodossiades

Rahnejat

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part J:

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Transmission efficiency is the main objective in the development of vehicular differential systems, comprising hypoid gear pairs. The overall aim is to contribute to improved vehicle fuel efficiency and thus levels of harmful emissions for modern desired eco-drive axles. Detailed predictive analysis plays an important role in this quest, particularly under realistic operating conditions, comprising high contact loads and shear rates. Under these conditions, the hypoid gear pairs are subject to mixed non-Newtonian thermo-elastohydrodynamic conditions, which is the approach undertaken in this paper. Such an approach for hypoid gear pair has not hitherto been reported in the literature.

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“…Due to the high entrainment speed in very narrow conjunctions of gear contacts, it is necessary to consider a non-Newtonian viscosity model. To incorporate the effect of shear thinning, a similar approach to that of Paouris et al [29] is undertaken, using the Havriliak and Negami [30] rheological model:…”

Section: Elastohydrodynamic Lubrication (Ehl)mentioning

confidence: 99%

Lubricated Loaded Tooth Contact Analysis and Non-Newtonian Thermoelastohydrodynamics of High-Performance Spur Gear Transmission Systems

2020

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Energy efficiency and functional reliability are the two key requirements in the design of high-performance transmissions. Therefore, a representative analysis replicating real operating conditions is essential. This paper presents the thermoelastohydrodynamic lubrication (TEHL) of meshing spur gear teeth of high-performance racing transmission systems, where high generated contact pressures and lubricant shear lead to non-Newtonian traction. The determination of the input contact geometry of meshing pairs as well as contact kinematics are essential steps for representative TEHL. These are incorporated in the current analysis through the use of Lubricated Loaded Tooth Contact Analysis (LLTCA), which is far more realistic than the traditional Tooth Contact Analysis (TCA). In addition, the effects of lubricant and flash surface temperature rise of contacting pairs, leading to the thermal thinning of lubricant, are taken into account using a thermal network model. Furthermore, high-speed contact kinematics lead to shear thinning of the lubricant and reduce the film thickness under non-Newtonian traction. This comprehensive approach based on established TEHL analysis, particularly including the effect of LLTCA on the TEHL of spur gears, has not hitherto been reported in literature.

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An Analytical Approach for Prediction of Elastohydrodynamic Friction with Inlet Shear Heating and Starvation

Cited by 24 publications

References 50 publications

3D Measurements of Lubricant and Surface Temperatures Within an Elastohydrodynamic Contact

3D Measurements of Lubricant and Surface Temperatures Within an Elastohydrodynamic Contact

Non-Newtonian mixed thermo-elastohydrodynamics of hypoid gear pairs

Lubricated Loaded Tooth Contact Analysis and Non-Newtonian Thermoelastohydrodynamics of High-Performance Spur Gear Transmission Systems

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