TRANSIENT THERMOELASTOHYDRODYNAMIC BEHAVI OR OF TILTING-PAD JOURNAL BEARINGS

The aim of this work is to study the thermal effects of tilting-pad jo urnal bearings during start-lip. A four-shoe tilting-pad journal beari ng is tested on an original device. Two theoretical approaches permit us to take into account the heat flux generated by viscous dissipation , the transient heat transfer and the viscosity variation across the f ilm thickness: these are the thermohydrodynamic (THD) and thermoelasto hydrodynamic (TEHD) models. The relevance of thermoelastic deformation s is emphasized by a comparison with theoretical THD and TEHD results: a decrease in radial bearing clearance is observed. The minimum trans ient period is about 1 or 2 min. A very good agrement between theoreti cal predictions and experimental data is obtained when both the solid deformations and heat transfer in the bearing elements are considered.