Variations from manufacturing can influence the overall pressure drop and subsequent flow rates through supply holes in such applications as film-cooling, transpiration cooling, and impingement cooling that are supplied by microchannels, pipe-flow systems, or secondary air systems. The inability to accurately predict flow rates has profound effects on engine operations. The objective of this study was to investigate the influence of several relevant manufacturing features that might occur for a cooling supply hole being fed by a range of channel configurations. The manufacturing variances included the ratio of the hole diameter to the channel width, the number of channel feeds (segments), the effect of hole overlap with respect to the channel sidewalls, and the channel Reynolds number. The results showed that the friction factors for the typically long channels in this study were independent of the tested inlet and exit hole configurations. The results also showed that the nondimensional pressure loss coefficients for the flow passing through the channel inlet holes and through the channel exit holes were found to be independent of the channel flow Reynolds number over the tested range. The geometric scaling ratio of the hole cross-sectional area to the channel cross-sectional area collapsed the pressure loss coefficients the best for both one and two flow segments for both the channel inlet and channel exit hole.

References

References
1.
Idel'chik
,
I. E.
,
1994
,
Handbook of Hydraulic Resistance
,
3rd ed.
,
CRC
,
Boca Raton
, FL.
2.
Miller
,
D. S.
,
1978
,
Internal Flow Systems
,
BHRA Fluid Engineering
,
Cranfield
,
UK
.
3.
Hay
,
N.
, and
Lampard
,
D.
,
1998
, “
Discharge Coefficient of Turbine Cooling Holes: A Review
,”
ASME J. Turbomach.
,
210
, pp
314
319
.10.1115/1.2841408
4.
Gritsch
,
M.
,
Schulz
,
A.
, and
Wittig
,
S.
,
2001
, “
Effect of Crossflows on the Discharge Coefficient of Film Cooling Holes With Varying Angles of Inclination and Orientation
,”
ASME J. Turbomach.
,
V123
, pp.
781
787
.10.1115/1.1397306
5.
Adkins
,
R. C.
, and
Gueroui
,
D.
,
1986
, “
An Improved Method for Accurate Prediction of Mass Flow Through Combustion Liner Holes
,”
ASME J. Eng. Gas Turbines Power
,
108
, pp.
491
497
.10.1115/1.3239935
6.
Engineering Sciences Data Unit 81039
,
1981
, “
Pressure Losses Across Orifice Plates, Perforated Plates and Thick Orifice Plates in Ducts
,” Internal Flow Panel, Engineering Sciences Data Unit Ltd., Specialised Printing Services Ltd., London.
7.
Munson
,
B.
,
Young
,
D.
, and
Okishi
,
T.
,
1998
,
Fundamentals of Fluid Mechanics
,
3rd ed.
,
John Wiley and Sons
,
Hoboken, NJ
.
8.
Petukhov
,
B. S.
,
1970
,
Advances in Heat Transfer
, Vol.
6
,
T. F.
Irvine
and
J. P.
Hartnett
, eds.,
Academic
,
New York
.
9.
Kline
,
S. J.
, and
McClintock
,
F. A.
,
1953
, “
Describing Uncertainties in Single-Sample Experiments
,”
ASME Mechanical Eng.
,
75
, pp.
3
8
.
10.
White
,
F. M.
,
1979
,
Fluid Mechanics
,
McGraw-Hill
,
New York
.
11.
Ansys
,
2009
, “
ANSYS FLUENT (version 12.0.16)
,” Ansys Inc., Canonsburg, PA.
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