Numerical investigation of mechanical losses of a titling-pad journal bearing

• Published in: IOP conference series. Earth and environmental science 2018-07, Vol.163 (1), p.12060
• Main Authors: Ding, A S, Xiao, Y B
• Format: Article
• Language: English
• Subjects: Aerodynamics; Cavitation; Cavitation flow; Experimental data; Gas flow; Journal bearings; Lubricants; Lubrication; Oil; Simulation; Three dimensional models; Turbulence models; Working conditions
• ISSN: 1755-1307; 1755-1315
• DOI: 10.1088/1755-1315/163/1/012060

Mechanical losses of large titling-pad journal bearings are increasing with higher rotational speed. However, mechanical losses of loaded and unloaded pads vary largely. This study analyzes the reason of varying mechanical losses in different pads. A three dimensional model is built for a full large tilting-pad journal bearing. The real backflow environment of journal bearings can be an important factor influencing lubricant viscosity and bearing mechanical loss. Thus, two boundaries, full-oil backflow and full-air backflow in two sides of the bearing, are simulated and compared with the experimental data of S.Taniguchi. Apart from the backflow lubricant, the gaseous cavitation and SST turbulence model are included in bearing simulations. Compared with experimental data, SST model is proved to be more suitable than laminar model for simulations. While the mechanical loss simulated by SST model with oil backflow is much higher than experimental data, the mechanical loss of the journal bearing by SST model with air backflow has small difference with experimental data. The pressure distributions in the bearing centerline simulated by oil backflow and air backflow are the same. Considering the full air backflow is in consistent with the real air environmental working condition, the air backflow is a suitable boundary for journal bearing simulations.