ISSN Online: 2377-424X
ISBN Print: 1-56032-797-9
International Heat Transfer Conference 11
FILM TEMPERATURE AND EFFECTIVENESS MEASUREMENTS ON A CYLINDRICAL LEADING EDGE FILM COOLING MODEL
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.
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.