NTRS - NASA Technical Reports Server

Back to Results
Turbomachinery Clearance ControlControlling interface clearances is the most cost effective method of enhancing turbomachinery performance. Seals control turbomachinery leakages, coolant flows and contribute to overall system rotordynamic stability. In many instances, sealing interfaces and coatings are sacrificial, like lubricants, giving up their integrity for the benefit of the component. They are subjected to abrasion, erosion, oxidation, incursive rubs, foreign object damage (FOD) and deposits as well as extremes in thermal, mechanical, aerodynamic and impact loadings. Tribological pairing of materials control how well and how long these interfaces will be effective in controlling flow. A variety of seal types and materials are required to satisfy turbomachinery sealing demands. These seals must be properly designed to maintain the interface clearances. In some cases, this will mean machining adjacent surfaces, yet in many other applications, coatings are employed for optimum performance. Many seals are coating composites fabricated on superstructures or substrates that are coated with sacrificial materials which can be refurbished either in situ or by removal, stripping, recoating and replacing until substrate life is exceeded. For blade and knife tip sealing an important class of materials known as abradables permit blade or knife rubbing without significant damage or wear to the rotating element while maintaining an effective sealing interface. Most such tip interfaces are passive, yet some, as for the high-pressure turbine (HPT) case or shroud, are actively controlled. This work presents an overview of turbomachinery sealing. 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 limitations issues.
Document ID
Document Type
Chupp, Raymond E. (General Electric Global Research Niksayuna, NY, United States)
Hendricks, Robert C. (NASA Glenn Research Center Cleveland, OH, United States)
Lattime, Scott B. (Timken Co. Canton, OH, United States)
Steinetz, Bruce M. (NASA Glenn Research Center Cleveland, OH, United States)
Aksit, Mahmut F. (Sabanci Univ. Istanbul, Turkey)
Date Acquired
August 24, 2013
Publication Date
January 1, 2007
Subject Category
Mechanical Engineering
Distribution Limits
Public Use Permitted.

Available Downloads

NameType 20070005016.pdf STI

Related Records

IDRelationTitle20060051674See AlsoSealing in Turbomachinery