Development of a Method for the Prediction of Pressure-Viscosity Coefficients of Lubricating Oils Based on Free-Volume Theory

Wu, Chaoyang; Klaus, E. E.; Duda, J. L.

doi:10.1115/1.3261861

Cited by 53 publications

(21 citation statements)

References 3 publications

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“…Many correlations are proposed in the literature to predict the pressure-viscosity coeffi cient based on the free volume theory 17 and bulk properties of liquid. 9 Also, there is much research 18,19 for the prediction of the pressure-viscosity coeffi cient α.…”

Section: Methodology Of the Predictionmentioning

confidence: 99%

Prediction of pressure–viscosity coefficient of lubricating oils based on sound velocity

Mia

Ohno

2009

Lubrication Science

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The pressure-viscosity coeffi cient is an important parameter in tribology. Experimentally, it is calculated using the high-pressure viscosity measurement. Also, the adiabatic bulk modulus is calculated using the sound velocity in the lubricating oil. Several lubricating oils are considered on the group basis such as traction oil, mineral oil, polyalphaolefi n oil, perfl uoropolyether oil and glycerol, depending on their molecular structure. Experimental pressure-viscosity coeffi cient is compared with the adiabatic bulk modulus. It is found that the pressure-viscosity coeffi cient increases exponentially with the adiabatic bulk modulus, and the relationship depends on the molecular structure of the lubricating oils. This study proposes two equations to predict the pressure-viscosity coeffi cient from the adiabatic bulk modulus based on sound velocity, one for the traction oil, and another for the paraffi nic mineral oil and the polyalphaolefi n oil.

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Section: Methodology Of the Predictionmentioning

confidence: 99%

Prediction of pressure–viscosity coefficient of lubricating oils based on sound velocity

Mia

Ohno

2009

Lubrication Science

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“…ρ 0 and η 0 are ρ and η, respectively, valued at atmospheric pressure, θ stands for local temperature, and α is the pressure-viscosity coefficient of the sealed fluid in SI units [29], α = 1.657 · 10 −9 + 2.332 · 10 −9 log 10 10 6 η 0 (θ inf ) ρ 0 (θ inf ) S 02 (8) where S 02 is the ASTM slope of the sealed fluid between 40…”

Section: Elastohydrodynamicsmentioning

confidence: 99%

Profile Optimization of Hydraulic, Polymeric, Sliding Seals by Minimizing an Objective Function of Leakage, Friction and Abrasive Wear

Nikas¹

2020

Lubricants

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Hydraulic dynamic seals for reciprocating or alternating motion are machine elements with widespread applications in the automotive, aerospace, marine, pharmaceutical and several other industrial sectors. They have been under commercial development for many decades, and are often met in critical positions, consuming a considerable amount of energy during operation. An objective function of mass leakage rate, friction force and an abrasive-wear representative term is proposed in the present study to evaluate the performance of hydraulic, polymeric sliding seals under suitable constraints. Using Variational Calculus, analytical and numerical techniques, the objective function is minimized, resulting in an optimal seal profile that maximizes sealing performance for given, steady-state operating conditions, in additional consideration of the structural integrity and manufacturability of the modified seal. The obtained seal shape and related pressure distribution are reminiscent of those for U-cup and step seals, designs that dominate the industry. In the course of the mathematical analysis, some major obstacles are documented that show how sensitive and complicated sealing performance really is.

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“…The viscosity of all the polymer solutions was adjusted at 37-39 mPa s at a test temperature of 40 • C. The polymer concentration in each polymer solution is listed in Tables 2 and 3. The viscosity-pressure coefficient α of polymer solutions, which was used for calculation of oil film thickness, was estimated by Wu et al's [15] formula proposed for the polymer solutions (1) where m base and m blend is ASTM-Walther's constant of base oil and polymer solution, respectively, and η 0 the atmospheric viscosity of polymer solution. Applicability of equation (1) was confirmed for measured viscosity of some polymer solutions with a falling ball-type viscometer.…”

Section: Polymers and Polymer Solutionsmentioning

confidence: 99%

Shear behaviour of polyalkylmethacrylate solutions under thin film lubrication

Muraki

Yamashina

2011

Proceedings of the Institution of Mechanical Engineers, Part J:

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Film-forming properties and traction were determined for the oils containing polyalkylmethacrylates (PAMAs) under a temperature of 40 • C and a rolling speed between 0.001 and 1 m/s with the disc-on-roller tester. Oil film thickness measurements were made under a pure rolling condition and traction measurements were made under the slide/roll ratio of 50 per cent. All the copolymers were synthesized in the base oil by a random copolymerization method. Difference in oil film thickness between polymer solutions became significant under the rolling speed below 0.1 m/s. Among non-functionalized homopolymers, PAMAs with branched alkyl group were superior to those with linear alkyl group in film-forming performance. In functionalized PAMAs, film-forming performance was affected by the functional group as well as the coexisting alkyl group. High-mole-concentration of functional group produced a greater oil film thickness than the corresponding low-mole-concentration PAMAs. This tendency was more marked for high-molecular-weight PAMAs. Among all the polymer solutions, high-molecular-weight PAMA with methyl group as a main component showed the thickest oil film, followed by high-molecularweight PAMA containing branched alkyl group and dimethylaminoethyl group. In the low speeds of the traction-speed curves, most PAMA solutions showed the effect of friction reduction, whose extent depended upon the type of alkyl group and functional group. It was inferred that the friction behaviour in the partial elastohydrodynamic lubrication (EHL) regime was considerably affected by the friction in the thin film lubrication based on the mutual interaction between polymer molecules.

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Development of a Method for the Prediction of Pressure-Viscosity Coefficients of Lubricating Oils Based on Free-Volume Theory

Cited by 53 publications

References 3 publications

Prediction of pressure–viscosity coefficient of lubricating oils based on sound velocity

Prediction of pressure–viscosity coefficient of lubricating oils based on sound velocity

Profile Optimization of Hydraulic, Polymeric, Sliding Seals by Minimizing an Objective Function of Leakage, Friction and Abrasive Wear

Shear behaviour of polyalkylmethacrylate solutions under thin film lubrication

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