An experimental investigation was conducted in a static ground test facility to determine the effectiveness of a serpentine inlet duct active flow control technique for two simulated flight conditions. The experiments used a scaled model of a compact, diffusing, serpentine, engine inlet duct developed by Lockheed Martin with a flow control technique using air injection through microjets at 1% of the inlet mass flow rate. The experimental results, in the form of total pressure measurements at the exit of the inlet, were used to predict the stability of a compression system through a parallel compressor model. The inlet duct was tested at cruise condition and angle of attack flight cases to determine the change in inlet performance due to flow control at different flight conditions. The experiments were run at an inlet throat Mach number of 0.55 and a resulting Reynolds number, based on the hydraulic diameter at the inlet throat, of 1.76*105. For both of the flight conditions tested, the flow control technique was found to reduce inlet distortion at the exit of the inlet by as much as 70% while increasing total pressure recovery by as much as 2%. The inlet total pressure profile was input in a parallel compressor model to predict the changes in stability margin of a compression system due to flow control for design and off-design flight conditions. Without flow control, both cases show a reduction in stability margin of 70%. With the addition of flow control, each case was able to recover a significant portion (up to 55%) of the undistorted stability margin. This flow control technique has improved the operating range of a compression system as compared to the same inlet duct without flow control.

1.
Hill
,
P.
, and
Peterson
,
C.
, 1992,
Mechanics and Thermodynamics of Propulsion
,
Addison-Wesley Publishing Co.
, Reading, MA.
2.
Bansod
,
P.
, and
Bradshaw
,
P.
, 1972, “
The Flow in S-Shaped Ducts
,”
Aeronaut. Q.
0001-9259,
23
, pp.
131
140
.
3.
Rowe
,
M.
, 1970, “
Measurements and Computations of Flow in Pipe Bends
,”
J. Fluid Mech.
0022-1120,
43
, Part 4, pp.
771
783
.
4.
Sullivan
,
J. P.
,
Murthy
,
S. N. B.
,
Davis
,
R.
, and
Hong
,
S.
, 1982, “
S-Shaped Duct Flows
,” Office of Naval Research Contract Number N-78-C-0710.
5.
Vakili
,
A.
,
Wu
,
J. M.
,
Liver
,
P.
, and
Bhat
,
M. K.
, 1983, “
An Experimental Investigation of Secondary Flows in an S-Shaped Circular Duct
,” NASA Final Report NAG3–233.
6.
Vakili
,
A.
,
Wu
,
J. M.
,
Liver
,
P.
, and
Bhat
,
M. K.
, 1983, “
Measurements of Compressible Secondary Flow in a Circular S-Duct
,” AIAA, Fluid and Plasma Dynamics Conference, 16th, Danvers, MA, July 12–14, 1983.
7.
Wellborn
,
S. R.
,
Reichert
,
B. A.
, and
Okiishi
,
T. H.
, 1992, “
An Experimental Investigation of the Flow in a Diffusing S-Duct
,”
AIAA/SAE/ASME/ASEE 28th Joint Propulsion Conference and Exhibit
, AIAA-92-3622.
8.
Povinelli
,
L. A.
, and
Towne
,
C. E.
, 1986, “
Viscous Analyses for Flow Through Subsonic and Supersonic Intakes
,”
AGARD Propulsion and Energetics Panel Meeting on Engine Response to Distorted Inflow Conditions
.
9.
Anderson
,
J. M.
, 2003, “
Non-Intrusive Sensing and Feedback Control of Serpentine Inlet Flow Distortion
,” Ph.D. Thesis, Virginia Tech, Blacksburg, VA.
10.
Anderson
,
B. H.
, and
Gibb
,
J.
, 1992, “
Study on Vortex Generator Flow Control for the Management of Inlet Distortion
,”
AIAA/SAE/ASME/ASEE 28th Joint Propulsion Conference and Exhibit
, AIAA-92-3177.
11.
Hamstra
,
J. W.
,
Miller
,
D. N.
,
Truax
,
P. P.
,
Anderson
,
B. A.
, and
Wendt
,
B. J.
, 2000, “
Active Inlet Flow Control Technology Demonstration
,”
22nd International Council of the Aeronautical Sciences
, ICA-6112.
12.
Jaw
,
L. C.
,
Cousins
,
W. T.
,
Wu
,
D. N.
, and
Bryg
,
D. J.
, 2001, “
Design and Test of a Semi-Passive Flow Control Device for Inlet Distortion Suppression
,”
ASME J. Turbomach.
0889-504X,
123
, pp.
9
13
.
13.
Reichert
,
B. A.
, and
Wendt
,
B. J.
, 1994, “
Improving Diffusing S-Duct Performance by Secondary Flow Control
,” AIAA 94-0365,
AIAA 32nd Aerospace Sciences Meeting and Exhibit
, Reno, NV.
14.
Reichert
,
B. A.
, and
Wendt
,
B. J.
, 1993, “
An Experimental Investigation of S-Duct Flow Control Using Arrays of Low-Profile Vortex Generators
,” AIAA 93-0018.
15.
Vakili
,
A. D.
,
Wu
,
J. M.
,
Liver
,
P.
, and
Bhat
,
M. K.
, 1985, “
Flow Control in a Diffusing S-Duct
,”
AIAA Shear Flow Control Conference
, AIAA-85–0524.
16.
Mazzawy
,
R. S.
, 1977, “
Multiple Segment Parallel Compressor Model for Circumferential Flow Distortion
,”
J. Eng. Power
0022-0825,
99
, pp.
288
296
.
17.
SAE S-16 Committee, 1978, ARP 1420, “
Gas Turbine Engine Inlet Flow Distortion Guidelines
,” Society of Automotive Engineers.
18.
Hale
,
A. A.
, and
Davis
,
M. W.
, Jr.
, 1992, “
DYNamic Turbine Engine Compressor Code, DYNTECC—Theory and Capabilities
,” AIAA-92-3190.
19.
Shahrokhi
,
K. A.
, and
Davis
,
M. W.
, 1995, “
Application of a Modified Dynamic Compression System Model to a Low-Aspect Ratio Fan: Effects of Inlet Distortion
,” AIAA 95-0301,
AIAA 33rd Aerospace Sciences Meeting and Exhibit
, Reno, NV.
20.
Reid
,
L.
, and
Moore
,
R. D.
, 1978, “
Performance of Single-Stage Axial-Flow Transonic Compressor With Rotor and Stator Aspect Ratios of 1.19 and 1.26, Respectively, and With Design Pressure Ratio of 1.82
,” NASA Technical Paper 1338, Lewis Research Center, Cleveland, OH.
21.
SAE S-16 Committee, 1983, AIR 1419, “
Inlet Total-Pressure-Distortion Considerations for Gas-Turbine Engines
,” Society of Automotive Engineers.
This content is only available via PDF.
You do not currently have access to this content.