Heat transfer, adiabatic effectiveness and injectant distributions downstream of single and double rows of film-cooling holes with compound angles

Abstract

Experimental results are presented which describe the development and structure of turbulent boundary layer flow downstream of single and double rows of film-cooling holes with compound angles. The film-cooling holes are inclined at an angle of 30 degrees when projected into the spanwisenormal (Y-Z) planes and at an angle of 35 degrees when projected into the streamwisenormal (X-Y) planes with respect to the test surface. Three configurations are used: (1) one row of film-cooling holes with a blowing ratio of m=0.5, (2) one row of film- cooling holes with a blowing ratio of m=1.0, and (3) two staggered row of film- cooling holes with a blowing ratio of m=0.5. Results indicate that the highest eta values are obtained when two rows of compound angle injection cooling holes are employed with a blowing ratio of m=0.5, and that the lowest eta values results when one row of compound angle injection cooling holes is employed with a blowing ratio of m=1.0. Near film cooling holes and for xd as high as 87, streamwise mean velocity and total pressure distributions show spanwise periodicity near the wall as a result of the discrete nature of film injection. At xd=10.2, injectant distributions are non-circular in spanwise normal planes. These distributions spread in lateral and normal directions as the boundary layer convects downstream.