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ISSN Online: 2377-424X

ISBN Print: 1-56032-797-9

International Heat Transfer Conference 11
August, 23-28, 1998, Kyongju, Korea

FILM TEMPERATURE AND EFFECTIVENESS MEASUREMENTS ON A CYLINDRICAL LEADING EDGE FILM COOLING MODEL

Get access (open in a dialog) DOI: 10.1615/IHTC11.1330
pages 571-576

Abstract

The film effectiveness and film temperature, on a cylindrical leading edge film cooling model were measured and presented. Tests were done in a low speed wind tunnel on a cylindrical model in a crossflow with two rows of film cooling holes. Mainstream Reynolds number based on the cylinder diameter was 100,900. The two rows of film cooling holes were located at ±15° from stagnation. The film holes were spaced 4-hole diameters apart and were angled 30° and 90° to the surface in the spanwise and streamwise directions, respectively. Two coolant blowing ratios (M = 0.4 and 1.2) and two free-stream turbulence levels (Tu = 1.0% and 7.1%) were tested. Film effectiveness distributions are measured using a transient liquid crystal technique. The cylinder surface is coated with a thin layer of thermochromic liquid crystals and a transient test is run to obtain the film effectiveness. The film effectiveness results are presented on only one side of the front half of the cylinder up to 70° from stagnation. Cold-wire is used to measure film coolant temperature distribution.
Film coolant temperature distributions are taken at 20°, 30°, 50°, 70° from stagnation and presented as mean temperature and temperature fluctuation. Results show that the increase in free-stream turbulence has very small effect on film effectiveness at high blowing ratio. For low blowing ratio, increase in free-stream turbulence intensity causes significant decrease in film cooling effectiveness. The film cooling jet behavior can be observed by the result of film coolant temperature measurement.