| Project Detail |
Gas turbines produce approximately 35% of the total electricity generation in the U.S. Improving their efficiency is important for reducing energy usage and carbon emissions. Similarly, higher efficiency aviation and other industrial turbines would improve the economics and reduce greenhouse gas emissions in these sectors. Gas turbine efficiency largely depends on the gas temperature at the inlet; the higher the temperature, the higher the efficiency. Gas turbine operational temperature is currently limited by its component materials, particularly those in the path of the hot gas such as turbine blades, vanes, nozzles, and shrouds. Turbine blades experience the greatest operational burden because they must concurrently withstand the highest temperatures and stresses. Currently, turbine blades are made of single crystal nickel (Ni)- or cobalt (Co)-based superalloys. After many years of refinements, their development has plateaued. There is a need to discover, develop, and implement novel materials that work at temperatures significantly higher than that of the Ni or Co superalloys if further efficiency gains are to be realized.
Project Innovation + Advantages:
A turbine engines combustion environment can rapidly degrade high temperature alloys, which means they must be coated. This coating must be able to expand with the alloy so it adheres during temperature cycling, prevent combustion gases from permeating to the underlying alloy, and possess ultra-low thermal conductivity to protect the alloy from high surface temperatures. The University of Virginia will develop a novel coating for high temperature alloys that enables both a dramatic increase in upper use temperature for turbine engine blades and increased engine efficiency. The proposed coating will achieve these goals via a mixture of oxides of rare earth metals with different mass, ionic size, and charge. This mixture enables adjusting the coating’s thermal expansion to match the underlying alloy and reduce its thermal conductivity. It will be manufactured using conventional air plasma spray or novel slurry-based processing to reduce cost and enable reparability. |
