Gas turbines component development

G.S. Corman, K.L. Luthra, and M.K. Bmn, Silicon Melt Infiltrated Ceramic Conqjosites — Processes and Properties Ch ter 16 in Progress In Ceramic Gas Turbine Development, Vol. II, Ceramic Gas Turbine Component Development and Evolution, Fabrication, NDE, Testing (md life Prediction, M. van Roode, M. Ferber, D. Richerson, eds., ASME Press, New York, USA, 2003. 

D. Anson and D.W. Richerson, The Benefits and Challenges of the Use of Ceramics in Gas Turbines, In Ceramic Gas Turbine Component Development and Characterization, eds M. van. Roode, M.K. Ferber, and D.W. Richerson, ASME press. New York, 2002. 

Cobalt-based alloys, in both wrought and cast forms, have also been developed for high-temperature applications such as gas turbine components, furnaces, and kilns. Alloy 25 (55Co-20Cr-10Ni-15W) (UNS R30605) is an example. Manufacturers are usually consulted in selecting these alloys. 

For the past 15 years, research and development of CMCs has been sustained because of their potential for military and commercial applications. The applications of interest include (1) aircraft engine components, such as combustors, turbines, compressors and exhaust nozzles (2) ground-based and automotive gas turbine components, such as combustors, first and second stage turbine vanes and blades, and shrouds (3) aerospace engines for missiles and reusable space vehicles and (4) industrial applications, such as heat exchangers, hot gas filters, and radiant burners. 

Fig. B. 1 shows simply how Kp., minus the (OM)/VV// component, varies with Co/IFand Tjo, for H = 4000 h and = 1 c/kWh. Horlock [4] has used this type of chart to compare three lines of development in gas turbine power generation ...

For land-based gas turbines, the overall plant output, efficiency, emissions, and reliability are the important variables. In a gas turbine, the processes of compression, combustion, and expansion do not occur in a single component, as they do in a diesel engine. They occur in components that can be developed separately. Therefore, other technologies and components can be added as needed to the basic components, or entirely new components can be substituted. 

Siemens-Westinghouse Power Corporation, of Pittsburgh, PA, with a subcontract to Allison Engine Company, evaluated a pressurized solid oxide fuel cell coupled with conventional gas turbine technology without a steam plant. The system was operated at a pressure of 7 atm. The fuel cell generated 16 MW of power and the gas turbine generated 4 MW of power. The process showed 67 % efficiency as developed. An efficiency of 70 % is deemed achievable with improvement in component design. The COE is predicted to be comparable to present day alternatives. NOx levels were less than 1 ppm. 

Both gas turbine and process heat versions of the HTGR are based on the demonstrated high-temperature capability of the fuel and core structure. However, some development in the metallic components, such as the turbine, hot duels and intermediate heat exchanger is necessary, Present commercial alloys would have limited lifetime under service conditions at 1650°F (899°C) and above. However, currently envisioned advancements in ceramics and carbon-carbon composites indicate that high-temperature nonmctallic substitutes for metallic alloys will soon be available. These materials advances are the key to making future application of the IITGR a reality. 

The application of Si3N4 ceramics as components for gas turbines is under development. First successful tests of those components have been carried out with 1350 °C turbine inlet temperatures. The further improvement of the turbine efficiency requires higher turbine inlet temperatures for this, additional coatings are necessary (Sect. 7.3). 

Yoshida M, Tanaka K, Tsuruzono S, Tatsuki T (1999) Development of Ceramic Components for Ceramic Gas Turbine Engine (CGT302). In Vincentini P (ed) Ceramics Getting Into the 2000 s, Part D, Elsevier, London, p 253... 

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