Gas Turbine Heat Transfer: Past and Future Challenges

The demand for gas turbines with increasing power and efe ciency calls for extremely high temperatures in the hot-gas sections of the engines. These temperatures can only be realized by employing sophisticated cooling schemes. Inadequate cooling may result in excessive material temperatures with reduced reliability and a lifetime of those parts subjected to the hot gas. Based on a survey of the different cooling techniques employed in modern gasturbineenginesandtheirapplicationin gasturbinecombustors, aswellasturbinecomponents,modernaspects and future developments are discussed. Results from laboratory experiments that help to understand the physical phenomena arepresented, as well as theoretical analyses. Thepossibleuse of ceramicmaterialsisdemonstrated by means of tests carried out at the Institut f ¨ ur Thermische Str ¨ omungsmaschinen, University of Karlsruhe. Besides describing current techniques, new developments are assessed and goals for future research are discussed.