Rotordynamic evaluation of hybrid damper seals with metal mesh elements

Abstract

Metal mesh hybrid damper seals (MHS) were proposed to be an alternative for brush hybrid pocket damper seals (PDS) in turbomachinery. The metal mesh hybrid damper seal is a hybrid of the pocket damper seal and the metal wire mesh seal. The primary objective of the research reported here is to verify if the MHS will leak less than the labyrinth seal and the PDS, while still enhancing the dynamic characteristics. The design of the previous MHS is modified and the leakage as well as the rotordynamic coefficients are estimated from experiments. The MHS leaks less than the conventional labyrinth seal and the conventional pocket damper seal. The rotordynamic characteristics were disappointing. The direct damping produced by the MHS was negative, while the direct stiffness was positive. The total effective damping was negative, rendering the system unstable. But the synchronous amplitude at the critical speed is reduced as the pressure increased. The reason for this anomaly was explained.