CFD Analysis of four-pad Journal Bearing with thermal Expansion

The effect of thermal expansion on the performance of tilting pad journal bearings (TPJBs) supporting gas-turbine generator rotors was investigated. As the temperature of the tilting pad increases to about 100 o C, thermal expansion can have a significant effect on the bearing performance. In this study, two-way fluid-structure interaction (2-FSI) simulations were performed with and without considering thermal expansion, and the results were compared with a 50% scaled-down model experiment. The tilting pad temperature measured in the experiment was 100.9o C. The simulation without considering thermal expansion predicted a temperature of 88.7 o C, and the simulation considering thermal expansion predicted a temperature of 99.7o C. Compared to the experimental results, the simulation without thermal expansion showed an error of 12.1%, and the simulation considering thermal expansion showed an error of 3.9%. These results indicated that the thermal expansion of the tilting pad should be considered to improve the accuracy of the computational fluid dynamics (CFD) simulation.