Unsteady Interaction Between a Transonic Turbine Stage and Downstream Components

Results from a numerical simulation of the unsteady flow through one quarter of the circumference of a transonic high-pressure turbine stage, transition duct, and low-pressure turbine first vane are presented and compared with experimental data. Analysis of the unsteady pressure field resulting from the simulation shows the effects of not only the rotor/stator interaction of the high-pressure turbine stage but also new details of the interaction between the blade and the downstream transition duct and low-pressure turbine vane. Blade trailing edge shocks propagate downstream, strike, and reflect off of the transition duct hub and/or downstream vane leading to high unsteady pressure on these downstream components. The reflection of these shocks from the downstream components back into the blade itself has also been found to increase the level of unsteady pressure fluctuations on the uncovered portion of the blade suction surface. In addition, the blade tip vortex has been found to have a moderately strong interaction with the downstream vane even with the considerable axial spacing between the two blade-rows. Fourier decomposition of the unsteady surface pressure of the blade and downstream low-pressure turbine vane shows the magnitude of the various frequencies contributing to the unsteady loads. Detailed comparisons between the computed unsteady surface pressure spectrum and the experimental data are shown along with a discussion of the various interaction mechanisms between the blade, transition duct, and downstream vane. These comparisons show overall good agreement between the simulation and experimental data and identify areas where further improvements in modeling are needed.Copyright © 2002 by ASME

[1]  Paul G. A. Cizmas,et al.  Parallel Computation of Turbine Blade Clocking , 1999 .

[2]  R. Takahashi,et al.  Unsteady hot streak simulation through a 1-1/2 stage turbine engine , 1991 .

[3]  H. Lomax,et al.  Thin-layer approximation and algebraic model for separated turbulent flows , 1978 .

[4]  Michael G. Dunn,et al.  The Effect of Airfoil Scaling on the Predicted Unsteady Loading on the Blade of a 1 and 1/2 Stage Transonic Turbine and a Comparison With Experimental Results , 2000 .

[5]  G. F. Pickett,et al.  Assessment of Unsteady Flows in Turbines , 1990 .

[6]  Douglas L. Sondak,et al.  Three-Dimensional Simulations of Airfoil Clocking in a 1-1/2 Stage Turbine , 2002 .

[7]  Roger L. Davis,et al.  Massively Parallel Simulation of the Unsteady Flow in an Axial Turbine Stage , 2002 .

[8]  Mark L. Celestina,et al.  A New Procedure for Simulating Unsteady Flows Through Turbomachinery Blade Passages , 1994 .

[9]  Philip C. E. Jorgenson,et al.  Explicit Runge-Kutta method for unsteady rotor/stator interaction , 1988 .

[10]  William W. Liou,et al.  Turbulence model assessment for shock wave/turbulent boundary-layer interaction in transonic and supersonic flows , 2000 .

[11]  Ralf Gombert,et al.  Unsteady Aerodynamical Blade Row Interaction in a New Multistage Research Turbine: Part 1 — Experimental Investigation , 2001 .

[12]  J. H. Wagner,et al.  Turbine Rotor-Stator Interaction , 1982 .

[13]  Michael B. Giles,et al.  Stator/rotor interaction in a transonic turbine , 1988 .

[14]  Reinhard Niehuis,et al.  Clocking Effects in a 1.5 Stage Axial Turbine—Steady and Unsteady Experimental Investigations Supported by Numerical Simulations , 2002 .

[15]  Reza S. Abhari,et al.  Influence of Vane-Blade Spacing on Transonic Turbine Stage Aerodynamics: Part II — Time-Resolved Data and Analysis , 1998 .

[16]  Michele Marconcini,et al.  Numerical Investigation of Airfoil Clocking in a Three-Stage Low-Pressure Turbine , 2002 .

[17]  D. Wilcox.  Turbulence modeling for CFD , 1993 .

[18]  Douglas L. Sondak,et al.  Computational Study of Clocking an Embedded Stage in a 4-Stage Industrial Turbine , 2001 .

[19]  Man Mohan Rai,et al.  Navier-Stokes simulations of rotor-stator interaction using patched and overlaid grids , 1985 .

[20]  Krishnan Mahesh,et al.  Modeling the Effect of Shock Unsteadiness in Shock-Wave / Turbulent Boundary Layer Interactions , 2004 .

[21]  R. A. Delaney,et al.  Vane-blade interaction in a transonic turbine. I - Aerodynamics , 1992 .

[22]  A. Jameson.  Time dependent calculations using multigrid, with applications to unsteady flows past airfoils and wings , 1991 .

[23]  Doyle Knight,et al.  RTO WG 10: CFD Validation for Shock Wave Turbulent Boundary Layer Interactions , 2002 .

[24]  David Dolling.  Unsteadiness of shock-induced turbulent separated flows - Some key questions , 2001 .

[25]  Juan J. Alonso,et al.  Development and Validation of a Massively Parallel Flow Solver for Turbomachinery Flows , 2001 .