Gas turbine (jet) engines are used to power most large commercial aircraft. From basic thermodynamic principles, gas turbine efficiency increases with increases in the maximum temperature of the gas flowing through the core of the engine. To enable engines to operate at higher gas temperatures, active cooling can be used to protect the metal components within the engine. This cooling is accomplished using internal coolant channels. The air coolant is exhausted through small holes in the surface where the air then forms a thin layer (film) of lower temperature fluid that protects the metal surface from the hot mainstream gases. Recent studies have shown that most all current film cooling designs are inherently flawed. This is because they are based on a presumption that laboratory testing at low speeds will provide performance data that is applicable to the high speeds that occur in actual engine operations. In fact, recent studies have shown that that at the high gas flow speeds that occur in the actual gas turbine engines, the performance is significantly different than found with low speed testing. Consequently, this study will focus on developing fundamental understanding of high speed effects on turbine film cooling performance, and developing new film cooling configurations specifically designed to operate at realistic engine speeds.
For this research program, a new high speed test facility will be constructed and used to test turbine cooling configurations at realistic Mach numbers. This test facility will allow direct measurements of fundamental flow and heat transfer mechanisms for film cooling using advanced shaped hole configurations operated at transonic speeds. Computational techniques will be used to determine optimum film cooling configurations that will mitigate the effects of supersonic flows within cooling holes. Furthermore, new turbine cooling configurations will be designed based on the wide range of geometrical configurations that are enabled by new additive manufacturing techniques with metal powder. These new designs are expected to substantially increase turbine cooling performance, allowing for the development of the next generation gas turbine engines operating at much higher core gas temperatures, with resulting higher efficiencies. The educational goals of the program include course development in advanced experimental methods, and fostering close interactions between students and our industrial partner to provide students with insight into real world engineering processes and techniques.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
