# Numerical Analysis of Elastohydrodynamic Contacts Using Power-law Lubricant With Special Reference to Water-based Hydraulic Fluids

Numerical Analysis of Elastohydrodynamic Contacts Using Power-law Lubricant With Special... A numerical solution of the elastohydrodynamic lubrication problem for pure rolling with non-Newtonian lubricants is outlined. The non-Newtonian rheological model used is a modified power-law, τ = K · γn. At low shear rate, γ < γb the lubricant is Newtonian, but when γ > γb the lubricant becomes non-Newtonian, τ = K · γn. At high shear rate (γ → ∞) the lubricant becomes Newtonian again with the same viscosity as the base lubricant. By using this rheological model a modified Reynolds' equation is derived. The influence of n-value and γb on the film thickness has been investigated. Plots of the pressure distribution and film thickness within the contact for fluids with G-values are the range 169–986 is presented. These G-values are typical for water-based hydraulic fluids. For fluids with low n-values (n < 0.5) the pressure profile approaches the Hertzian pressure distribution and the minimum film thickness will be that given by the base fluid viscosity. A new minimum film thickness formula for fluids with low G-values is proposed: H̄min = (105 + 0.0246 · G)U0.68 · W−0.073 Presented at the 42nd Annual Meeting in Anaheim, California May 11–14, 1987 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png A S L E Transactions Taylor & Francis

# Numerical Analysis of Elastohydrodynamic Contacts Using Power-law Lubricant With Special Reference to Water-based Hydraulic Fluids

, Volume 30 (4): 7 – Jun 13, 1986

## Numerical Analysis of Elastohydrodynamic Contacts Using Power-law Lubricant With Special Reference to Water-based Hydraulic Fluids

, Volume 30 (4): 7 – Jun 13, 1986

### Abstract

A numerical solution of the elastohydrodynamic lubrication problem for pure rolling with non-Newtonian lubricants is outlined. The non-Newtonian rheological model used is a modified power-law, τ = K · γn. At low shear rate, γ < γb the lubricant is Newtonian, but when γ > γb the lubricant becomes non-Newtonian, τ = K · γn. At high shear rate (γ → ∞) the lubricant becomes Newtonian again with the same viscosity as the base lubricant. By using this rheological model a modified Reynolds' equation is derived. The influence of n-value and γb on the film thickness has been investigated. Plots of the pressure distribution and film thickness within the contact for fluids with G-values are the range 169–986 is presented. These G-values are typical for water-based hydraulic fluids. For fluids with low n-values (n < 0.5) the pressure profile approaches the Hertzian pressure distribution and the minimum film thickness will be that given by the base fluid viscosity. A new minimum film thickness formula for fluids with low G-values is proposed: H̄min = (105 + 0.0246 · G)U0.68 · W−0.073 Presented at the 42nd Annual Meeting in Anaheim, California May 11–14, 1987

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# References (6)

Publisher
Taylor & Francis
Copyright Taylor & Francis Group, LLC
ISSN
0569-8197
DOI
10.1080/05698198708981785
Publisher site
See Article on Publisher Site

### Abstract

A numerical solution of the elastohydrodynamic lubrication problem for pure rolling with non-Newtonian lubricants is outlined. The non-Newtonian rheological model used is a modified power-law, τ = K · γn. At low shear rate, γ < γb the lubricant is Newtonian, but when γ > γb the lubricant becomes non-Newtonian, τ = K · γn. At high shear rate (γ → ∞) the lubricant becomes Newtonian again with the same viscosity as the base lubricant. By using this rheological model a modified Reynolds' equation is derived. The influence of n-value and γb on the film thickness has been investigated. Plots of the pressure distribution and film thickness within the contact for fluids with G-values are the range 169–986 is presented. These G-values are typical for water-based hydraulic fluids. For fluids with low n-values (n < 0.5) the pressure profile approaches the Hertzian pressure distribution and the minimum film thickness will be that given by the base fluid viscosity. A new minimum film thickness formula for fluids with low G-values is proposed: H̄min = (105 + 0.0246 · G)U0.68 · W−0.073 Presented at the 42nd Annual Meeting in Anaheim, California May 11–14, 1987

### Journal

A S L E TransactionsTaylor & Francis

Published: Jun 13, 1986