Question 322Steam Plants - 1st Asst/Chief70% to pass
The labyrinth seals used on rotating steam turbine shafts reduces external leakage by causing _______________.
AI Explanation
The correct answer is B) successive pressure drops through the seal stages.
Labyrinth seals used on rotating steam turbine shafts work by creating a series of small clearances between the rotating shaft and the stationary seal housing. As the steam passes through these clearances, the pressure is reduced in a stepwise manner, preventing external leakage. The successive pressure drops through the seal stages are the key mechanism that makes labyrinth seals effective in reducing leakage.
The other options are incorrect because they do not accurately describe the primary function of labyrinth seals. Increased turbulence (A) is a secondary effect, and temperature drops (C) and pressure increases (D) are the opposite of how labyrinth seals actually operate.
Related Questions
#320 Most auxiliary turbine feed pumps do not require an external source of gland sealing steam because they _______________.#321 Packing rings installed on auxiliary turbines are generally lubricated by _______________.#323 Where are moisture shields located in a main propulsion steam turbine? #324 When turbine rotor shafts extend through the casing, an external source of sealing steam is used in conjunction with labyrinth packing to _______________.#325 Labyrinth seals used to reduce leakage around a turbine shaft are constructed of _______________.