Experimental Studies of Lubricant Flow and Friction in Partially Filled Gaps
Starved lubrication is an important strategy for minimizing the amount of lubricant needed, and also inevitably occurs during idling and fail-safe lubrication. In this regime, however, the flow of the lubricant and the related friction coefficients are yet to be fully understood. This research aims...
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Format: | Article |
Language: | English |
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MDPI AG
2018-12-01
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Series: | Lubricants |
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Online Access: | https://www.mdpi.com/2075-4442/6/4/110 |
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author | Michael Müller Lukas Stahl Georg-Peter Ostermeyer |
author_facet | Michael Müller Lukas Stahl Georg-Peter Ostermeyer |
author_sort | Michael Müller |
collection | DOAJ |
description | Starved lubrication is an important strategy for minimizing the amount of lubricant needed, and also inevitably occurs during idling and fail-safe lubrication. In this regime, however, the flow of the lubricant and the related friction coefficients are yet to be fully understood. This research aims to make fundamental contributions to the understanding of contact mechanics of partially lubricated contacts. Recent experiments with a pin-on-disk tribometer examined the microscopic behavior of partially filled gaps. Using a new experimental setup on a macroscale, new insights into partially filled gaps with rough surfaces were gained. This work presents the systematic analyses of the lubricant flow, friction coefficients, and other variables over a wide range of friction parameters. Distinct friction behaviors were observed, and similar effects occur on both the micro and macroscale. The experimental results show that a typical Stribeck characteristic is visible regarding not only the relative velocity, but also regarding the lubricant filling level in the gap. The fluid exhibits a variety of flow patterns for various velocities and viscosities. The patterns relate to different friction regimes, such as dry friction and mixed lubrication. It is concluded that the filling level is a valid parameter for regulating the transition from dry friction to hydrodynamic lubrication. These findings are quantified regarding the filling level and it is shown that for the identification of the friction regimes the filling level is an independent parameter in addition to the established parameters like speed, viscosity and pressure. |
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format | Article |
id | doaj.art-592fcfdcca794d3fb1b0c2178ab6f6e7 |
institution | Directory Open Access Journal |
issn | 2075-4442 |
language | English |
last_indexed | 2024-04-11T13:42:54Z |
publishDate | 2018-12-01 |
publisher | MDPI AG |
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series | Lubricants |
spelling | doaj.art-592fcfdcca794d3fb1b0c2178ab6f6e72022-12-22T04:21:11ZengMDPI AGLubricants2075-44422018-12-016411010.3390/lubricants6040110lubricants6040110Experimental Studies of Lubricant Flow and Friction in Partially Filled GapsMichael Müller0Lukas Stahl1Georg-Peter Ostermeyer2Institut für Dynamik und Schwingungen, Technische Universität Braunschweig, 38106 Braunschweig, GermanyInstitut für Dynamik und Schwingungen, Technische Universität Braunschweig, 38106 Braunschweig, GermanyInstitut für Dynamik und Schwingungen, Technische Universität Braunschweig, 38106 Braunschweig, GermanyStarved lubrication is an important strategy for minimizing the amount of lubricant needed, and also inevitably occurs during idling and fail-safe lubrication. In this regime, however, the flow of the lubricant and the related friction coefficients are yet to be fully understood. This research aims to make fundamental contributions to the understanding of contact mechanics of partially lubricated contacts. Recent experiments with a pin-on-disk tribometer examined the microscopic behavior of partially filled gaps. Using a new experimental setup on a macroscale, new insights into partially filled gaps with rough surfaces were gained. This work presents the systematic analyses of the lubricant flow, friction coefficients, and other variables over a wide range of friction parameters. Distinct friction behaviors were observed, and similar effects occur on both the micro and macroscale. The experimental results show that a typical Stribeck characteristic is visible regarding not only the relative velocity, but also regarding the lubricant filling level in the gap. The fluid exhibits a variety of flow patterns for various velocities and viscosities. The patterns relate to different friction regimes, such as dry friction and mixed lubrication. It is concluded that the filling level is a valid parameter for regulating the transition from dry friction to hydrodynamic lubrication. These findings are quantified regarding the filling level and it is shown that for the identification of the friction regimes the filling level is an independent parameter in addition to the established parameters like speed, viscosity and pressure.https://www.mdpi.com/2075-4442/6/4/110starved lubricationpartially filled gaplubricatedflow patternscoefficient of friction |
spellingShingle | Michael Müller Lukas Stahl Georg-Peter Ostermeyer Experimental Studies of Lubricant Flow and Friction in Partially Filled Gaps Lubricants starved lubrication partially filled gap lubricated flow patterns coefficient of friction |
title | Experimental Studies of Lubricant Flow and Friction in Partially Filled Gaps |
title_full | Experimental Studies of Lubricant Flow and Friction in Partially Filled Gaps |
title_fullStr | Experimental Studies of Lubricant Flow and Friction in Partially Filled Gaps |
title_full_unstemmed | Experimental Studies of Lubricant Flow and Friction in Partially Filled Gaps |
title_short | Experimental Studies of Lubricant Flow and Friction in Partially Filled Gaps |
title_sort | experimental studies of lubricant flow and friction in partially filled gaps |
topic | starved lubrication partially filled gap lubricated flow patterns coefficient of friction |
url | https://www.mdpi.com/2075-4442/6/4/110 |
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