Computation of Discrete-Hole Film Cooling: A Hydrodynamic Study

Abstract

Hydrodynamic plots are presented from a numerical study conducted on a three dimensional film cooling geometry that includes the main flow, injection hole, and the plenum. The fully elliptic Navier-Stokes equations were solved over a body fitted grid using the control volume method. Turbulence closure was achieved using the k-ε turbulence model. The results presented include contour plots of the resultant velocity at hole exit, as well as streamwise mean velocity and turbulence intensity contours at several cross-stream planes. Computations were performed for blowing ratios of 0.5 and 1.0, and a density ratio of 2. The injection hole was 12.7 mm in diameter, 3.5 diameters long, and inclined at 35° to the streamwise direction. Results obtained from this analysis are compared with the available experimental results. Whereas the overall agreement is good, important differences were found. Compared to the experimental jet, the computed jet showed (a) a larger vertical velocity at hole exit, (b) a smaller lateral spread in the downstream region, especially at low blowing ratios.