MIDN 1/C Clayton S. Pelzer - 11th Company
The Effects of Acceleration on Film Cooling in Gas Turbine Engines
Advisers: Professor Ralph J. Volino, Assistant Professor Ronald J. Warzoha, Mechanical and Nuclear Engineering DepartmentMajor: Mechanical and Nuclear Engineering Department
Description:
Gas turbine engines are used in many different applications, including many that are pertinent to the Navy, such as aircraft engines. Increasing the temperature inside of these engines increases their efficiency, but the material strength of structural components limits the maximum temperatures inside the engine. To allow for high temperatures, engine blades are designed with film cooling holes that blow cool air over the surface of the blades, protecting them from high temperatures up to 2000 °C inside the turbines. There are many factors that affect film cooling, including acceleration of flow over the surface of the blade. Its impacts on the film cooling process are not fully understood. In order to observe the direct effects of acceleration at different magnitudes, a test section was constructed to model the interactions of flow over a gas turbine blade. Based on temperature and velocity measurements within the test section, heat transfer coefficients and film cooling effectiveness were determined. Knowledge of these quantities allows prediction of turbine blade temperature under engine conditions. As the acceleration of flow over film cooling holes increases, the effectiveness of the film cooling increases. Large accelerations decrease the turbulence of the flow and in turn, limit the mixing of film cooling jets with the main flow. As a result, the jets retain their structure longer and remain closer to the surface of the blade, thereby providing higher effectiveness.