Velocity Measurements in Transonic Turbomachinery Blade Cascade Flow

Increasing turbine inlet temperature for improved efficiency has resulted in a need for full-coverage film cooling for the first turbine blade and vane. In this project, the possible use of under-expanded jets for turbine-blade cooling was investigated experimentally.

Two-dimensional velocity measurements were performed in a linear turbomachinery blade cascade, together with surface pressure measurements and flow visualization. There was special emphasis on the Mach number and turbulence distribution in the blade wake flow and a recently proposed turbine-blade cooling system, using high-speed cooling jets.