Abstract
Pressure fluctuation in stern tube sealing for large ships was studied. An analysis was verified by using a test stand having seal rings of 1250 mm diameter.
The pressure fluctuation was caused by the following three factors; the inertia movement of oil accompanying with the shaft vibration in radial direction, the volume variation of a recess due to the vibration of sealing liner in axial direction and the propagation of pressure fluctuation generated in a recess.
Pressure fluctuation calculated by simulating a 170, 000 ton freight vessel was identical with a fluctuation observed in the vessel.
Air bag in a recess is effective for suppressing the pressure fluctuation caused by a resonance of oil in an oil groove with an axial shaft vibration.
