Labyrinth seal

These interlock, to produce the long characteristic path which slows leakage.

[1] Labyrinth seals on rotating shafts provide non-contact sealing action by controlling the passage of fluid through a variety of chambers by centrifugal motion, as well as by the formation of controlled fluid vortices.

At higher speeds, centrifugal motion forces the liquid towards the outside and therefore away from any passages.

Many gas turbine engines, having high rotational speeds, use labyrinth seals due to their lack of friction and long life.

In these applications, it is the long and difficult path and the formation of controlled fluid vortices plus some limited contact-sealing action that creates the seal.