vibrations-excited-in-ring-shaped-spaces-2Schematic depiction of the air and labyrinth vibrations inthe area of the TOBIExample of a vibration excitement through airvibrations in a ring-shaped space:SSTOBIAerodynamic excitement via labyrinth sealsAlford force of the high-pressure turbinePressure vibrations in the cooling air supplyTF-30 Engine typesP-111+P-414 P-100Vibration-exciting performance [ kw]0.00750.600.450.030.150-0.15IIIIIIIVVVIIncreased leakageair flow at lowfan inletpressureSection SS:reduced6-nodal diameter vibrationof the inner labyrinth ringHPT diskVibratinglabyrinthRing space withair vibrationsTest results from engines for determining the causes ofvibrations