Quantitative viscosity mapping using fluorescence lifetime measurements
File(s)
Published version
Author(s)
Dench, J
Morgan, N
Wong, J
Type
Journal Article
Abstract
Lubricant viscosity is a key driver in both the tribological performance and energy efficiency of a lubricated contact. Elastohydrodynamic (EHD) lubrication produces very high pressures and shear rates, conditions hard to replicate using conventional rheometry. In situ rheological measurements within a typical contact are therefore important to investigate how a fluid behaves under such conditions. Molecular rotors provide such an opportunity to extract the local viscosity of a fluid under EHD lubrication. The validity of such an application is shown by comparing local viscosity measurements obtained using molecular rotors and fluorescence lifetime measurements, in a model EHD lubricant, with reference measurements using conventional rheometry techniques. The appropriateness of standard methods used in tribology for high-pressure rheometry (combining friction and film thickness measurements) has been verified when the flow of EHD lubricant is homogeneous and linear. A simple procedure for calibrating the fluorescence lifetime of molecular rotors at elevated pressure for viscosity measurements is proposed.
Date Issued
2016-12-30
Date Acceptance
2016-12-16
Citation
Tribology Letters, 2016, 65
ISSN
1573-2711
Publisher
Springer Verlag
Journal / Book Title
Tribology Letters
Volume
65
Copyright Statement
© 2016 The Authors.This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
License URL
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Shell Research Limited
Engineering & Physical Science Research Council (EPSRC)
Grant Number
EP/J015385/1
PT22478 - PO 4550059303
EP/L023202/1
Subjects
Mechanical Engineering & Transports
0912 Materials Engineering
0913 Mechanical Engineering
Publication Status
Published
Article Number
25