Numerical Study of Single Pad Externally Adjustable 120° Pad Bearing Using Fluid Structure Interaction

High-speed turbomachinery like turbine generators and marine propulsion systems uses special fluid film bearing called externally adjustable pad bearing due to their great advantages. The principal feature of this bearing is to alter the radial clearance and film thickness along the circumferential direction to improve the bearing performance parameters. In the present study, the effect of radial and tilt adjustment of 120 pad both in upward (or negative) and downward (or positive) direction on the bearing performance is predicted for various eccentricity ratios using the CFD technique. Later the influence of fluid film pressure on the bearing pad is examined using the FSI technique. Furthermore, the effect of eccentricity ratio on the bearing performance and also on pad structure is also analyzed using CFD coupled FSI analysis. The solution technique of the present numerical analysis is validated with the already published literature and the results are in good agreement. The numerical results suggest that for bearing with negative radial and negative tilt adjustment, bearing performance is superior compared to the other adjustments. However, the structural deformation is also significant for the negative radial and negative tilt adjustment. It is also observed that pad deformation increases with the increase in eccentricity ratio as there has been a rise in fluid film pressure.