The forced response of a low aspect-ratio transonic fan due to different inlet distortions was predicted using an integrated time-domain aeroelasticity model. A time-accurate, nonlinear viscous, unsteady flow representation was coupled to a linear modal model obtained from a standard finite element formulation. The predictions were checked against the results obtained from a previous experimental program known as “Augmented Damping of Low-aspect-ratio Fans” (ADLARF). Unsteady blade surface pressures, due to inlet distortions created by screens mounted in the intake inlet duct, were measured along a streamline at 85 percent blade span. Three resonant conditions, namely 1F/3EO, 1T & 2F/8EO and 2S/8EO, were considered. Both the amplitude and the phase of the unsteady pressure fluctuations were predicted with and without the blade flexibility. The actual blade displacements and the amount of aerodynamic damping were also computed for the former case. A whole-assembly mesh with about 2,000,000 points was used in some of the computations. Although there were some uncertainties about the aerodynamic boundary conditions, the overall agreement between the experimental and predicted results was found to be reasonably good. The inclusion of the blade motion was shown to have an effect on the unsteady pressure distribution, especially for the 2F/1T case. It was concluded that a full representation of the blade forced response phenomenon should include this feature.

Issue Section:
Gas Turbines: Structures and Dynamics
Keywords:
vibrations, failure (mechanical), aerodynamics, damping, gas turbines, rotors
Topics:
Aeroelasticity, Blades, Damping, Flow (Dynamics), Pressure, Vibration, Computation, Resonance, Boundary-value problems
1.
Giles, M. B., 1987, “Calculation of Unsteady Wake/Rotor Interaction,” AIAA Paper No. 87-0006.
2.
Rai
,
M. M.
,
1987
, “
Navier-Stokes Simulations of Rotor/Stator Interaction Using Patched and Overlaid Grids
,”
AIAA J. Propul. Power
,
3
, pp.
387
–
396
.
3.
Dawes, W. N., 1988, “Development of a Three-Dimensional Navier-Stokes Solver for Application to all Types of Turbomachinery,” ASME Paper 88-GT-70.
4.
Arnone, A., 1995, “Multigrid Methods for Turbomachinery Navier-Stokes Calculations,” Solution Techniques for Large-Scale CFD Problems, W. G. Habashi, ed., John Wiley and Sons, New York, pp. 293–332.
5.
Denton, J. D., 1990, “The Calculation of 3D Viscous Flows Through Multistage Turbomachines.” ASME Paper 90-GT-19.
6.
He
,
L.
, 1997, “Computation of Unsteady Flow Through Steam Turbine Bladerows at Partial Admission,” IMechE J of Power & Energy, 211.
7.
Hall, K. C., and Clark, W. S., 1991, “Calculation of Unsteady Linearized Euler Flows in Cascades Using Harmonically Deforming Grids,” 6th international Symposium on UAATP, Univ. of Notre Dame, Sept. 15–19.
8.
Hall, K. C., and Clark, W. S., 1999, “A Time Linearised Navier-Stokes Analysis of Stall Flutter,” ASME Paper 99-GT-389.
9.
Green, J. S., and Marshall, J. G., 1999, “Forced Response Prediction Within the Design Process,” 3rd European Conference on Turbomachinery, IMECHE Paper C557/121/99.
10.
Vahdati
,
M.
, and
Imregun
,
M.
,
1996
, “
A Non-linear Aeroelasticity Analysis of a Fan Blade Using Unstructured Dynamic Meshes.
”
J. Mech. Eng. Sci., Part C
210
, pp.
549
–
563
.
11.
Sbardella, L., Sayma, A. I., and Imregun, M., 1997, “Semi-Unstructured Mesh Generator for Flow Calculations in Axial Turbomachinery Blading,” 18th International Symposium on Unsteady Aerodynamics and Aeroelasticity of Turbomachines, T. Franson, ed., Kluwer Academic Publishers, Dordrecht.
12.
Baldwin, B. S., and Barth, T. J., 1991, “A One-Equation Turbulence Transport Model for High Reynolds Number Wall-Bounded Flows,” Paper No. AIAA 91-0610.
13.
Swanson
,
R. C.
, and
Turkel
,
E.
,
1992
, “
On Central-Difference and Upwind Schemes
,”
J. Comput. Phys.
,
101
, pp.
292
–
306
.
14.
Jorgenson
,
P. C.
, and
Turkel
,
E.
,
1993
, “
Central Difference TVD Schemes for Time Dependent and Steady State Problems
,”
J. Comput. Phys.
,
107
, pp.
297
–
308
.
15.
Marshall, J. G., and Imregun, M., 1996, “An Analysis of the Aeroelastic Behaviour of a Typical Fan Blade With Emphasis on Flutter Mechanisms,” ASME Paper 96-GT-78.
16.
Ballhaus
,
W. F.
, and
Goorjian
,
P. M.
,
1978
, “
Computation of Unsteady Transonic Flows by the Indicial Method
,”
AIAA J.
,
16
, pp.
117
–
124
.
17.
Bendiksen, O. O., 1991, “A New Approach to Computational Aeroelasticity,” AIAA Paper 91-0939.
18.
Srivastava
,
R.
,
Sankar
,
L. N.
,
Reddy
,
T. S. R.
, and
Huff
,
D. L.
,
1991
, “
Application of an Efficient Hybrid Scheme for Aeroelastic Analysis of Advanced Propellers
,”
Journal of Propulsion
,
7
, pp.
767
–
775
.
19.
Bakhle
,
M. A.
,
Reddy
,
T. S. R.
, and
Keith
,
T. G.
,
1992
, “
Time Domain Flutter Analysis of Cascades Using a Full-Potential Solver
,”
AIAA J.
,
30
, pp.
163
–
170
.
20.
Rabe, D. C., Bolcs, A., and Russler, P., 1995, “Influence of Inlet Distortion on Transonic Compressor Blades Loading,” AIAA Paper 95-2461.
21.
Manwaring, S. R., Rabe, D. C., Lorence, C. B., and Wadia, A. R., 1996, “Inlet Distortion Generated Forced Response of a Low Aspect Ratio Transonic Fan,” ASME Paper 96-GT-376.
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