Influence of Oil Conducting Ducts on Squeeze Film Damper Forces

Abstract Squeeze film dampers (SFDs) are critical components in rotating machinery, designed to reduce vibration amplitudes and improve rotor dynamic stability. During operation, oil is evacuated from the SFD to prevent excessive temperature rise, typically through slits in the end seals. To maintain system performance, a continuous oil supply is required. Therefore, an oil distribution duct channels the oil from the pump to an inlet orifice and then to several feeding orifices. Recently, industry has shown interest in an oil evacuation system that mirrors the design of the oil delivery system. The design consists of recovery orifices that extract oil from the SFD into a recovery duct, where it is then discharged through an exit orifice. Traditional models assume constant pressure within both feeding and recovery ducts. In this study, a model for the feeding and recovery duct flows is proposed and validated against computational fluid dynamics (CFD) results. The duct model is coupled with a bulk-flow (BF) solution for the flow in the SFD. Contrary to the constant pressure assumption, the model shows that the pressure within the ducts oscillates, following the whirling motion of the rotor. The amplitude of these oscillations increases with the orbit radius, the rotor angular speed, and the reduction of duct cross-sectional area. It is shown that under certain operating conditions these oscillations can have a non-negligible influence on the forces generated by the SFD.