EHL simulation using the free-volume viscosity model

článek v časopise - ostatní, Jost

angličtina

The free-volume viscosity model can accurately predict the temperature pressure viscosity relationship of lubricants. However, it is seldom used in elastohydrodynamic lubrication (EHL) simulation. This paper presents the application of the free-volume viscosity model in a Newtonian EHL simulation of a squalane-lubricated circular contact. Good agreement is observed between available experimental data and simulation results. The pressure viscosity coefficients fit from viscometer data are also discussed. A recently developed definition of the coefficient is used to compare the coefficient value extracted from EHL film thickness interference measurements. Results indicate that the coefficient values from the curve fitting and EHL film thickness extraction agree well which has not been previously observed. Two factors help achieve this agreement: the new coefficient definition and smaller prediction error when using the Hamrock Dowson formula in the cases studied. The effects of different pressure viscosity relationships, including the exponential model, the Roelands model and the free volume model, are investigated through an example with bright stock mineral oil. It is found that the real pressure viscosity behavior predicted by the free volume model yields a higher viscosity at the low pressure area which results in a larger central film thickness. Therefore, due to use of the free-volume model, the present results are more consistent with experimental observations than previously reported numerical results.

lubrication; film thickness

LIU, Y.; WANG, Q.J.;WANG, W.; HU, Y.,; ZHU, D.; KŘUPKA, I.; HARTL, M.

2006

15. 7. 2006

Springer Netherlands

Holandsko

1023-8883

Tribology Letters

23

1

Spojené státy americké

27

37

11