Which type of seal is characterized by non-contacting behavior using geometric steps to impede flow?

• A. Labyrinth Seals
• B. Carbon Seals
• C. Seal Land
• D. O-Rings

Answer: (A)

Non-contacting seals use geometry to block flow rather than pressing a lip against a surface. A labyrinth seal creates a long, winding path with multiple tight clearance steps between the rotating and stationary parts. As fluid tries to leak from the high-pressure side to the low-pressure side, it must navigate this maze, and each bend and narrow gap adds resistance and causes pressure drops. The overall leakage becomes very small while the parts stay separated, so wear is minimized—crucial for high-speed turbine engine components. This is different from carbon seals, which rely on a carbon face rubbing against a mating surface; and from elastomeric O-rings, which seal by compression and contact. The term seal land isn’t a standard non-contacting, stepped-path seal type. Thus, the non-contacting, step-based maze that impedes flow defines a labyrinth seal.