Dynamic Characteristics of a Non-symmetric Tilting Pad Journal Bearing
Because tilting-pad journal bearings are more stable and efficient than conventional bearings, they have been commonly applied to many rotating machinery applications. Most of the studies about steady state and dynamic characteristics of tilting-pad journal bearings are usually evaluated by means of thermo hydrodynamic models assuming nominal dimensions for the bearing. However machining errors could lead to actual bearing geometry and dimensions different from the nominal ones. In particular for tilting-pad journal bearing the asymmetry of the bearing geometry is the principal cause of unexpected behavior. In this paper a theoretical analysis on dynamic characteristics of a five-pad tilting-pad journal bearing is investigated with non-nominal geometry, that is, different thickness for each pad. The dynamic coefficients of a five-pad tilting-pad journal bearing with a nominal diameter of 100 mm, length-to-diameter ratio (L/D) of 0.7 are evaluated versus rotor rotational speed, load direction and static load. Then, the analytical results of the non-nominal bearing are compared to those of a bearing having nominal (i.e. ideal) geometry.
KeywordsTilting-pad journal bearing Analytical model Non-nominal bearing Dynamic coefficients Five pads
- 6.Dang, P.V., Chatterton, S., Pennacchi, P., Vania, A., Cangioli, F.: Behavior of a tilting–pad journal bearing with different load directions. ASME Paper No. DETC2015-46598, vol. 8 (2015). https://doi.org/10.1115/detc2015-46598
- 8.Dang, P.V., Chatterton, S., Pennacchi, P., Vania, A., Cangioli, F.: Behavior of tilting-pad journal bearings with large machining error on pads. ASME Turbo Expo, Paper No. GT GT2016-56674 (2016)Google Scholar
- 10.Chatterton, S., Dang, P.V., Pennacchi, P., Vania, A.: A test rig for evaluating tilting–pad journal bearing characteristics. In: 9th International Conference on Rotor Dynamics IFToMM ICORD, Milan, Italy, pp. 921–930 (2014)Google Scholar
- 11.Jones, G.J., Martin, F.A.: Geometry effects in tilting-pad journal bearings. In: The 33rd Annual Meeting in Dearborn, Michigan (1978)Google Scholar
- 12.Strzelecki, S.: Dynamic characteristics of tilting 5-pads journal bearing with asymmetric support of pads. In: Sixth International Conference on Rotor Dynamics (IFToMM), University of New South Wales, Sydney, Australia, pp. 807–814 (2002)Google Scholar