Air Riding Seal Technology for Advanced Gas Turbine Engines

To meet future power generation needs, Florida Turbine Technologies, Inc. (FTT) proposes the development of an innovative design approach to provide a highly durable contactless air riding rotating-to-static seal. Rotating-to-static seals are critical components of all gas turbine engines. The seals can significantly affect the efficiency, operability, and durability of a gas turbine engine. As such, any improvements to these seals are highly desirable. Improvements may come in the form of reduced leakage and/or improved seal durability. Air riding seals provide benefits that other rotating-to-static seals cannot achieve. These include reduced gaps resulting in lower leakages and improved durability due to the fact that the static seal is not designed to contact the rotating component while maintaining very tight clearances to control leakage to the lowest levels possible. The efficiency of future power production facilities must be increased to address well-known problems of increasing global energy usage and emissions from the combustion of carbon-based fuels. These emissions, carbon dioxide in particular, are increasingly accepted as a significant cause and contributor to global warming. More and more, initiatives to reduce carbon dioxide emissions are being legislated throughout the world. The goal of this effort is to introduce an improved rotating-to-static seal to be used in turbomachinery. The proposed seal is designed to passively follow the rotating surface during transients, allowing a near constant leakage gap throughout all engine operating conditions, and drastically reduces the chance of rubbing. Preliminary studies show air riding seals also provide benefits by reducing leakage and overall size of the seal. These benefits have a significant impact to small/mini gas turbine engines as it allows the use of a tangential onboard injector (TOBI), and a cooled turbine allowing for higher turbine inlet temperatures. All of these improvements ultimately result in greater cycle efficiency and reduced fuel consumption.