Turbulent thermohydrodynamic lubrication models compared with measurements

Abstract

The authors derived a three-dimensional turbulent thermohydrodynamic lubrication (THL) model (model A), based on the isothermal turbulent lubrication model developed in 1971 by Aoki and Harada. The Aoki-Harada theory is characterized by its modified definition of mixing length which enables its velocity profile in the lubricating oil film to agree very well with measurements not only in the log region (full turbulent layer) but also in the viscous sublayer and the buffer layer. On the other hand, Taniguchi et al. derived a three-dimensional turbulent THL model (model B), based on the isothermal turbulent lubrication model developed in 1965 by Ng and Pan, and Mikami et al. derived a two-dimensional turbulent THL model (model C), based on the Aoki-Harada model. The present authors coded and used these three different turbulent THL models to predict the static performance of a four-pad tilting pad journal bearing of a real size and to compare the predictions with measurements. The theoretical results given by model A were found to be in better agreement with measurements obtained in a test rig of the bearing, compared with those given by models B and C.