Sealing in Turbomachinery

Clearance control is of paramout importance to turbomachinery designers and is required to meet today's aggressive power output, efficiency, and operational life goals. Excessive clearance lead to losses in cycle efficiency, flow instabilities, and hot gas ingestion into disk cavities. Insufficient clearances limit coolant flows and cause interface rubbing, overheating downstream components and damaging interfaces, thus limiting compoment life. Designers have put renewed attention on clearance control, as it is often the most cost-effective method to enhance system performance. Advanced concepts and proper material selection continue to play important roles in maintaining reterface clearances to enable the system to meet design goals. This worl presetns an overview of turbomachinery sealing to control clearances. Areas covered include characteristics of gas and steam turbine sealing applications and environments, benefits of sealing, types of standard static and dynamics seals, advanced seal designs, as well as life and limitation issues.