The film cooling performance and velocity field were investigated for discrete round holes inclined at an injection angle of 55 deg. Results are compared to typical round film cooling holes, with an injection angle of 35 deg. All experiments in this study were performed at a density ratio of DR = 1.6, using cryogenic cooling of the injected air. Centerline and lateral distributions of effectiveness were obtained for a range of momentum flux ratios. Thermal field and two component mean velocity and turbulence intensity measurements were made at a momentum flux ratio that was within the range of maximum spatially averaged effectiveness. Compared to round holes with 35 deg injection angle, the 55 deg holes showed only a slight degradation in centerline effectiveness for low momentum flux ratios, while a significant reduction in effectiveness was seen at high momentum flux ratios. The thermal field for the 55 deg round holes indicated a faster decay of cooling capacity for the 55 deg round holes. The high turbulence levels for the 55 deg round hole coincided with the sharp velocity gradients between the jet and free stream, and the decay of turbulence levels with downstream distance was found to be similar to those for a 35 deg hole.

1.
Foster
N. W.
, and
Lampard
D.
,
1980
, “
The Flow and Film Cooling Effectiveness Following Injection Through a Row of Holes
,”
ASME Journal of Engineering for Power
, Vol.
102
, pp.
584
588
.
2.
Pedersen
D. R.
,
Eckert
E. R. G.
, and
Goldstein
R. J.
,
1977
, “
Film Cooling With Large Density Differences Between the Mainstream and the Secondary Fluid Measured by the Heat-Mass Transfer Analogy
,”
ASME Journal of Heat Transfer
, Vol.
99
, pp.
620
627
.
3.
Pietrzyk, J. R., 1989, “Experimental Study of the Interaction of Dense Jets with a Crossflow for Gas Turbine Applications,” Ph. D Thesis, University of Texas at Austin.
4.
Pietrzyk
J. R.
,
Bogard
D. G.
, and
Crawford
M. E.
,
1990
, “
Effects of Density Ratio on the Hydrodynamics of Film Cooling
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
112
, pp.
437
443
.
5.
Schmidt
D. L.
,
Sen
B.
, and
Bogard
D. G.
,
1996
, “
Film Cooling With Compound Angle Holes: Adiabatic Effectiveness
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
118
, pp.
807
813
.
6.
Sinha
A. K.
,
Bogard
D. G.
, and
Crawford
M. E.
,
1991
, “
Film Cooling Effectiveness Downstream of a Single Row of Holes With Variable Density Ratio
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
113
, pp.
442
449
.
7.
Thole, K. A., Sinha, A. K., Bogard, D. G., and Crawford, M. E., 1992, “Mean Temperature Measurements of Jets With a Crossflow for Gas Turbine Film Cooling Application,” in: Rotating Machinery Transport Phenomena, J. H. Kim and W. J. Yang, eds., Hemisphere Pub. Corp., New York.
This content is only available via PDF.
You do not currently have access to this content.