THEORETICAL AND EXPERIMENTAL COMPARISONS FOR ROTORDYNAMIC COEFFICIENTS OF A MULTI-SCRATCHED TILTING PAD JOURNAL BEARING

This paper presents a Thermos-Elasto-Hydrodynamics model (TEHD) based on a mass conservative generalized Reynolds equation, coupled with 3D energy equations for the oil film, and a full 3D thermo-mechanical model for the pads. The model uses a regularization technique to consider film thickness discontinuities created by scratches. The numerical results are compared to the experimental results obtained from a rocker-backed, five tilting pads journal bearing TPJB with single and multiple scratches. The numerical model achieved good agreement especially with respect to pad temperatures and dynamic coefficients. Discrepancies were observed at low speed but only on the stiffness in the load direction. The numerical model shows significant drop in the pressure field at the location of the scratches, and a significant pressure rise between two consecutive scratches accompanied by a decrease of film thickness.