Effect of Diffusively Shaped Holes on the Turbulent Flow Field of a Film Cooling Plate

The gas turbine blades with diffusion film cooling holes are newly developed blade structures in the hydrogen combustion gas turbine, which has an extremely high inlet gas temperature (1700°C). The Fluid Machinery Laboratory of Nagoya Institute of Technology conducted firstly a new research on the turbulent flow field over the gas turbine blade with diffusion film cooling holes in Japan. Normal-type and X-type hot wires were applied in the measurement of the flow field. The streamwise mean velocity, the turbulent intensities and the Reynolds shear stress were obtained. The experimental data were processed as spatial distributions in the planes of downstream direction and spanwise respectively. The effect of the diffusion hole on the improvement of the turbulent flow field for the film cooling of gas turbines was demonstrated.