Aero-Thermal Cascade Tunnel Flow Quality: Turbulence Generation and Prediction

摘要

Turbine blade temperatures in modern turbine engines are the limiting factor inthe advancement of aircraft propulsion today. One reason for the blades' thermal stress failure has to do with the traverse effects of turbulent flow over the blades--the more turbulence in the flow, the greater the heat transfer to the blade. Of concern here are both freestream and boundary layer turbulence. Therefore, the focus of much research today is on studying turbine blade models with post-burner turbulent flow conditions in order to design and build blades around the predicted failure levels and coordinates. The focus of this paper is on the generation of the turbulence characteristics which will be necessary for use in cascade wind tunnel facilities. Methods of turbulence generation and turbulence trends are analyzed with the main parameter being turbulence intensity variation with both lateral and streamwise location. The results presented here are a complete turbulent flow field description for a turbulence generation method, supporting the 'air off' grid configuration as ready for use and research while demanding revision of the 'air on' high turbulence generation method.