Abstract In this paper, the thermal behavior of a marine thruster lip seal package operating fully submerged under realistic conditions was investigated. The study was conducted with a focus on developing a condition monitoring system for such a package. The package consisted of three nitrile-butadiene rubber (NBR) lip seals of nominal diameter 300 mm. A tungsten carbide coated stainless steel shaft liner was used as the counter-face. A custom test device was built to measure the near-lip and near-liner temperatures, in addition to the sub-surface contact temperature of three samples of the seals within the package (n = 3, nine seals in total). The thermal behavior of the seal package was influenced the most by the rotational speed of the shaft, followed by the pressure differentials over the seals and the temperature of the gearbox oil. The radial force of the seals was influenced by the position of the seal in the seal package. The wear of the seals appeared to depend on the lubrication condition at the contact. The thermal behaviors of the elements of the seal package were found to be highly interdependent. The results demonstrated the potential and suitability of thermal monitoring for condition monitoring systems for marine thruster lip seal packages.
White et al. (2026) studied this question.