Sealing between rotating and stationary parts is very important for modern turbomachines, including aeroengines, land based gas turbines, steam turbines and industrial turbines.

A number of advanced seal structures have been developed for aeroengines, and then other turbine machines. Seals have repeatedly shown high performance benefit-to-cost benefit ratios in recent studies as a result of their high performance payoff and their relative low development costs. Advanced engine seals show promise of reducing engine losses and maintaining these performance benefits over engine service intervals.

New seals coupled with improved design codes give the designer better control of engine secondary flows - critical in extracting the maximum useful work out of these high power density engines.

Several typical seals are described as follows.