Within the gas turbine market, there is tremendous commercial pressure on gas turbine manufacturers to increase the plant efficiency and reduce specific costs whilst continuing to meet the ever more stringent emission limits. The US Government has responded to this commercial pressure by agreeing with gas turbine manufacturers a jointly funded programme (total $900m) to develop an Advanced Turbine System with the major objectives to increase plant efficiency above 60% (combined cycle) and to reduce emissions of NOx, CO and UHC to less than 8ppm, 20ppm and 20 ppm respectively, while in Japan a similar project is being pursued by a consortium of four major industrial groups. In order to remain in the lead gas turbine manufacturers in Europe must match these perfommance targets, or preferably better them.
As is clear from the above, the major drivers for advanced gas turbine technology are improved efficiency, reduced emission and lower costs. This proposal for the application of ceramic matrix composite (CMC) materials to gas turbines is submitted by the industrial partner European Gas Turbines (EGT) in response to these drivers. If this proposal on CMC's is sucessful, it will lead to a 50% increase in efficiency.
In a combined cycle, higher efficiency is obtained from the use of higher turbine inlet temperatures in the cycle However the current and possibly future metallic materials have reached their limit in terms of strength, oxidation and corrosion resistance at about 1,000 C and the only promising alternative seems to be CMC materials whicl will require no cooling air. This air can then be usefully used at higher temperature thus producing more worl from the cycle. The removal of cooling also reduces the costs of the machine by minimizing the number of duct and air passages in machine components, particularly blading. Because of their high specific stiffness and strength, CMC materials is the best choice to achieve a thrust to weight ratio of 15:1 or higher required by future aeroengines. It should be pointed out that both US and Japanese programmes mentioned above have identified CMCs as the key materials for the same reasons.
The project will address the major stumbling blocks that have hindered the industrial application of CMCs. In particular, it will:
Establish CMC design data pertinent to the operating conditions of the gas turbine components.
Develop generic design, analysis and lifing methodologies at three levels for CMCs
Design, fabricate and test CMC combustor can and liner to validate the design, analysis and lifing philosophies developed
Funding SchemeCSC - Cost-sharing contracts
1755 ZG Petten