What is the purpose of labyrinth seals around the compressor shaft?

• A. To dissipate heat from the rotor.
• B. To minimize oil leakage and leakage paths while permitting rotor movement.
• C. To seal the combustor.
• D. To cool the compressor inlet.

Answer: (B)

Labyrinth seals around the compressor shaft are designed to minimize leakage from the bearing area into the compressor while still allowing the shaft to rotate freely. They achieve this with a tortuous, non-contact path created by a series of interlocking ridges and gaps. Each turn adds resistance to flow, so oil and air leakage along the shaft is greatly reduced without requiring tight metal-to-metal contact. This lets the rotor move at high speed with minimal wear and accommodates thermal expansion and shaft runout. It’s about keeping oil contained and leakage paths limited, not about cooling the inlet or sealing the combustor or dissipating rotor heat.