Gas Turbine Engines: Seals

In turbomachines, seals control clearances. Excessive clearances lead to losses in cycle efficiency, flow instabilities, and hot gas ingestion into disk cavities. Insufficient clearances limit coolant flows and cause interface rubbing, possible overheating of downstream components, and damage interfaces; thus limiting component life. Clearance control is often the most cost effective method to enhance system performance. Advanced concepts and proper material selection continue to play important roles in maintaining interface clearances to enable the system to meet design goals. This chapter presents an overview of sealing in turbomachines. Keywords: turbomachines; seals; engines; clearance control; gas turbines; materials; shroud