Design, Analysis and Development of Squeeze Film Dampers for High Speed Machines

Present day state of the art in the design of turbo machines has given much scope to the flexible rotor bearing system. The most recurring problem in rotor dynamics is the excessive steady state synchronous vibration levels. Squeeze film dampers (SFD) are the essential components of high-speed turbomachines since they offer the advantage of dissipation of vibration energy and hence prevent rotor dynamic instabilities. A squeeze film damper is used between the bearing and its foundation to reduce the unbalance forces transmitted to the pedestal by introducing an additional damping and there by reduce the amplitude of vibration to acceptable limit. This work highlights the design and development of squeeze film dampers for high-speed machines in a more generic way. The first phase of the work involves the study of the effect of SFD on rotor dynamics based on the parameters like, damping ratio, logarithmic decrement and Transmissibility. A theoretical model Is generated incorporating the said parameters. The dynamic analysis, which is of two fold. Is carried out using ARMD software. The rotor dynamic effects are found without SFD and with SFD. The second phase of the work deals with experimental investigation on a journal-bearing test rig with SFD supports up to a speed of 1800 rpm. At the end, the vibrations obtained through theoretical analysis and experimental investigations are tabulated. It Is concluded that vibration levels are reduced using SFD for the specified optimum inputs.