Advanced Vane & Blade Cooling for Turbine Engines

MC2 vane/blade cooling approach increases allowable turbine inlet temperature by nearly 350oF without film cooling.

Gas turbine engine technology is constantly challenged to operate at higher efficiencies, leading to a push towards stoichiometric combustion and ever higher combustor outlet temperatures. In a modern gas turbine engine, these temperatures can exceed the blade and disk material limits by 600 °F or more, necessitating both internal and film cooling schemes in addition to the use of thermal barrier coatings. Internal convective cooling is often inadequate, particularly in the stagnation region of the blade. Both internal and film cooling approaches can lead to significant performance penalties in the engine, due to thermal mixing and total pressure losses.

Micro Cooling Concepts has developed a turbine blade cooling concept that provides enhanced internal impingement cooling effectiveness via the use of micro-structured impingement surfaces. These surfaces significantly increase the cooling capability of the impinging flow, as compared to a conventional untextured surface. Eliminating film cooling prevents thermal mixing losses and preserves the bleed air for other roles in the engine.

In a NASA-sponsored development project, MC2 built and tested 5 turbine vanes of 4 different designs, and compared them in a head-to-head test with a conventional turbine vane in a 2000oF turbine test rig. In the tests, the best-performing MC2 vane showed a 21% reduction in non-dimensional temperature compared to the conventional vane (see figure below).

Scaling the results to engine temperatures, one can expect that the MC2 vane would allow a 345oF increase in turbine inlet temperature, which is equivalent to a 25% increase in specific power. This increase translates directly into fuel economy.