Interturbine diffusers provide continuity between HP and LP turbines while diffusing the flow upstream of the LP turbine. Increasing the mean turbine diameter offers the potential advantage of reducing the flow factor in the following stages, leading to increased efficiency. The flows associated with these interturbine diffusers differ from those in simple annular diffusers both as a consequence of their high-curvature S-shaped geometry and of the presence of wakes created by the upstream turbine. It is shown that even the simplest two-dimensional wakes result in significantly modified flows through such ducts. These introduce strong secondary flows demonstrating that fully three-dimensional, viscous analysis methods are essential for correct performance modeling.

Issue Section:
Research Papers
Topics:
Blades, Diffusers, Wakes, Flow (Dynamics), Turbines, Ducts, Geometry, Modeling
1.
Amman, C. A., Nordenson, G. E., and Razinskiy, E. H., 1971, “The Turbine Interstage Diffuser,” GMR-1083 Report, General Motors Emissions Research Department.
2.
Britchford, K. M., Manners, A. P., McGuirk, J. J., and Stevens, S. J., 1993, “Measurement and Prediction of Flow in Annular S-Shaped Ducts,” Engineering and Turbulence Measurements 2.
3.
Dominy
R. G.
, and
Hodson
H. P.
,
1993
, “
An Investigation of Factors Influencing the Calibration of Five-Hole Probes for Three-Dimensional Flow Measurements
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
115
, pp.
513
–
519
.
4.
ESDU, 1976, “Introduction to Design and Performance Data for Diffusers,” Engineering Science Data Unit, data item 66027.
5.
Fottner, L., ed., 1990, “Test Cases for Computation of Internal Flows in Aero Engine Components,” AGARD-AR-275, pp. 309–321.
6.
Moore
J.
, and
Moore
J. G.
,
1985
, “
Performance Evaluation of Linear Turbine Cascades Using Three-Dimensional Viscous Flow Calculations
,”
ASME Journal of Engineering for Gas Turbines and Power
, Vol.
107
, pp.
969
–
975
.
7.
Moore, J. G., 1985, “An Elliptic Calculation Procedure for Three-Dimensional Viscous Flow,” AGARD-LS-140 4.1–4.16.
8.
Pfeil
H.
, and
Going
M.
,
1987
, “
Measurements of the Turbulent Boundary Layer in the Diffuser Behind an Axial Compressor
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
109
, pp.
405
–
412
.
9.
Quest, J., and Scholtz, N., 1982, “Experimental Results of Annular Diffusers Behind a Turbine Stage,” [in German], FVV-Heft 302.
10.
Taylor, A. M. P. K., Whitelaw, J. H., and Yianneskis, M., 1982, “Developing Flows in S-Shaped Ducts. Part 1: Square Cross-Section Duct,” NASA Contractor Report CR3550.
11.
Towne, C. E., 1984, “Calculation of Viscous Flow in Curved Ducts and Comparison With Experimental Data,” Paper No. AIAA-84-0531.
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