The adiabatic, steady-state liquid crystal technique was used to measure surface adiabatic film cooling effectiveness values in the near-hole region (X / D < 10). A parametric study was conducted for a single row of short holes (L / D ≤ 3) fed by a narrow plenum (H / D = 1). Film cooling effectiveness values are presented and compared for various L / D ratios (0.66 to 3.0), three different blowing ratios (0.5, 1.0, and 1.5), two different plenum feed configurations (co-flow and counter flow), and two different injection angles (35° and 90°). Injection hole geometery and plenum feed direction were found to significantly affect short hole film cooling performance. Under certain conditions, comparable or improved coverage was achieved with 90° holes as with 35° holes. This result has important implications for manufacturing of thin-walled film-cooled blades or vanes.

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