Determination of Damping Coefficient of a Bump Foil Squeeze Film Damper

The present investigation is aiming to get better squeeze film dampers which are normally used in high speed jet engines to minimize small amplitude large force vibrations. The investigation was started with squeeze film dampers employing conventional lubricating oils. Magneto rheological fluids are then used to enhance the viscosity characteristics of the fluid under the influence of magnetic fields in order to improve the damper performances. It is observed that the dynamic characteristics of the damper with magneto rheological fluids are enhanced. Further to improve the damper performance, few modifications in the damper assembly are carried out in this research work. A good amount of reduction in the amplitude of vibrations is observed in these modified squeeze film dampers coupled with magneto rheological fluids. This research work discusses dual and triple clearance squeeze film dampers and bump foil squeeze film damper, also subjected to variation in temperature. Dynamic characteristics are found to be decreasing as the viscosity of the fluid decreases with rise in temperature of the fluid.