Limiting gap current-generated turbine oscillations - by reducing component of current in direction of rotation of oscillating vector

摘要

The method is applicable to steam or gas turbines or compressors with gap in contact-less seals between rotating and stationary components. The desired effect is achieved by reducing the circumferential component of the gap current in the direction in which the oscillating vector of the natural oscillation rotates, or by increasing a circumferential component of the gap current in the opposite direction. For units, other than compressors, in which the oscillation vector rotates in the same direction as the turbine rotor, the circumferential vector in the direction of rotor rotations may be so reduced that the gap current force component, which leads by 90 deg., is reduced, eliminated or reversed in direction. These results may be achieved by incorporating guide means such as vanes, ribs, profiles, ducts etc., in or before the gap.