A new fluid film force model of elliptical bearing: Modelling and case studies

AbstractThe fluid film force model plays a very important role in the non-linear dynamic analysis of a rotor-bearing system. Based on the assumption of the short journal bearing, the fluid film pressure distribution in an elliptical bearing is obtained in terms of the Reynolds equation and the dynamic Gumbel boundary conditions. According to the structural characteristic of elliptical bearing and the integral of fluid film pressure distribution, the fluid force model is formulated. A numerical experiment on the Jeffcott flexible-rotor model is given to show that the model is effective when length-diameter ratio is smaller than 0.6, and the computing cost for dynamical response of rotor-bearing is reduced. Finally, the dynamical behaviour and bifurcation of a 200 MW turbine set are numerically obtained applying the new fluid film force model.