Velocity and concentration field measurements and large eddy simulation of a shaped film cooling hole

Abstract

The 3D velocity and scalar concentration fields from a laidback fan-shaped film cooling hole are measured using Magnetic Resonance Velocimetry (MRV) and Magnetic Resonance Concentration (MRC). The velocity and scalar concentration fields of the same geometry are also obtained using Large Eddy Simulation (LES). The geometry under consideration features a single film cooling hole with a 30° inclination angle and 7° forward and lateral expansion angles. The results are compared to an existing adiabatic effectiveness experiment using infrared imaging of an identical geometry (Schroeder and Thole, 2014). Flow separation is observed inside the hole in the LES and MRV. The separated region in the LES is symmetrically located, but it is offset to a lateral side in the MRV which slightly skews the scalar concentration field to one side. Comparisons of the LES with the MRV and MRC experiments show good agreement in the velocity and scalar concentration field elsewhere throughout the 3D domain. Despite some disagreement in the adiabatic effectiveness values with the IR experiment immediately after injection, there is good agreement downstream of injection between the IR experiment and the LES and MRC. Differences in the concentration field can be attributed to differences in the in–hole velocity field. The results suggest that the mean position of the region of separation inside the hole is geometrically sensitive.