LAUSR

The present investigation considers the effects of special roughness patterns on impingement target surfaces to improve the effectiveness and surface heat transfer augmentation levels of impingement jet array cooling. This investigation uses various sizes, distributions, shapes, and patterns of surface roughness elements for impingement cooling augmentation. The surface roughness shapes considered here are the rectangle and triangle, in combination with larger rectangle roughness. The configurations considered include 1) arrays of small rectangle roughness, 2) arrays of small triangle roughness, 3) combinations of small rectangle roughness and large roughness together, and 4) combinations of small triangle roughness and large roughness together. Tests are performed at impingement jet Reynolds numbers of 900, 1500, 5000, and 11,000. Local and overall impingement cooling performance depends upon the shape of the roughness elements, as well as upon the jet Reynolds number. Depending upon the magnitude of the...