Identification of leakage tendency and optimum operating parameters on a newly fitted stern tube seal

Abstract

Stern tube seal is widely used in marine transportation to provide improved sealing for watertight integrity at higher shaft revolution. If the operating parameters exceed the optimum operating cooling water pressure with reference to variable initial operating and boundary conditions, deformation which can lead to excessive leaking may occur. This research studies on the factors contributing to leakage tendency of a newly fitted Stern Tube Seal Seat Assembly (STSSA). The study involved verification on the STSSA current design by means of leakage tendency identification, thus proposing optimum operating parameters to avoid excessive leaking. This is implemented by using numerical modelling by means of Fluid Solid Interaction (FSI) simulation model. Numerical modelling results in terms of deformation at the STSSA running surface are compared with actual field data on a specific STSSA. The results shows leakage tendency is subject to occur at operating cooling water pressure of 3 bars based on Fluid Film Lubrication (FFL) outcome characteristic which is stress distribution and deformation. Furthermore, the operating cooling water pressure of 2.5 bars is proposed as the optimum operating parameters based on the resultant STSSA deformation on not exceeding limits of 0.025 mm.