A new turbulent thermohydrodynamic performance analysis of tilting pad journal bearing based on a k-ε model and comparison with measurements

Abstract

The oil film flow in large journal bearings usually transits from laminar flow to turbulent one with increase in shaft speed. This paper presents a new turbulent THL (thermo-hydrodynamic lubrication) model based on the low-Reynolds-number k-ε model to predict the performance of such bearings, while conventional turbulent THL models are based on the mixing length theory. The static performance of a four-pad tilting pad journal bearing of a real size is predicted with the new turbulent THL model and the predictions are found to agree well with the measurements presented in the open literature, including the temperature inflection characteristics of maximum pad surface temperature, a hump increase of minimum oil film thickness corresponding to the temperature inflection with shaft speed and also a steep increase of friction loss resulting from the transition to the turbulent flow of the oil film with increase in shaft speed. The new turbulent THL model is also shown to give the predictions comparable with those with the conventional turbulent THL model. However, the program developed by applying the new model is found to give the predictions surely, when compared with the one applying the conventional model. It is concluded that the new turbulent THL model can replace the conventional one in designing the turbulent journal bearings.

Keywords

• tribology
• turbulent thermohydrodynamic lubrication model
• k-ε model
• tilting pad journal bearing
• performance