Theoretical and experimental study on lip seal losses in large high-speed rotors

This paper is devoted to the theoretical study of rubbermetal friction with particular reference to a lip seal for large high-speed rotor applications. The paper, starting from previously published mathematical models related to friction estimations, presents a semi-analytical mathematical model to estimate friction loss induced by rubber lip seals. The sliding friction model is formulated on the basis of rubber and metal surface properties. Viscoelastic and hysteretic properties of the rubber are considered as function of temperature and excitation frequency. The metal surface profile is modelled as a superimposition of base ideal peak profiles. Finally, the friction coefficient is modelled as a function of temperature, frequency and contact pressure. A preliminary validation of the model is achieved by comparing the estimated friction torque provided by the model with the friction torque measured on an actual rotor-stator system at different operating temperatures.