This study examines the effects of periodic inflow unsteadiness on the flow development through fishtail-shaped diffusers utilized on small gas-turbine engines. In this application, periodic unsteadiness is caused by a jet-wake type of flow discharging from each passage of the centrifugal compressor impeller. The study consists of detailed measurements in a large-scale fishtail diffuser rig with a geometry that is typical of those used in small gas-turbine engines. Measurements of the transient velocity field have been performed at five cross-sectional planes throughout the diffuser using a miniature hot-wire probe with four wires. These measurements involve frequencies of inflow unsteadiness corresponding to design as well as off-design operating conditions. Results indicate significant effects of inflow unsteadiness at the low end of the tested frequencies on the time-averaged streamwise and cross-flow velocity fields in the diffuser. This is shown to translate into a notable impact on the pressure recovery. In addition to providing insight into the physics of this flow, the experimental results presented here constitute a detailed and accurate data set that can be used to validate computational-fluid-dynamics algorithms for this type of flow.
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March 2004
Technical Papers
Effects of Periodic Inflow Unsteadiness on the Time-Averaged Velocity Field and Pressure Recovery of a Diffusing Bend With Strong Curvature
M. I. Yaras,
M. I. Yaras
Department of Mechanical and Aerospace Engineering, Carleton University, Ottawa, Canada K1S 5B6
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P. Orsi
P. Orsi
Department of Mechanical and Aerospace Engineering, Carleton University, Ottawa, Canada K1S 5B6
Search for other works by this author on:
M. I. Yaras
Department of Mechanical and Aerospace Engineering, Carleton University, Ottawa, Canada K1S 5B6
P. Orsi
Department of Mechanical and Aerospace Engineering, Carleton University, Ottawa, Canada K1S 5B6
Contributed by the Fluids Engineering Division for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received by the Fluids Engineering Division October 30, 2002; revised manuscript received October 2, 2003. Associate Editor: A. K. Prasad.
J. Fluids Eng. Mar 2004, 126(2): 229-237 (9 pages)
Published Online: May 3, 2004
Article history
Received:
October 30, 2002
Revised:
October 2, 2003
Online:
May 3, 2004
Citation
Yaras , M. I., and Orsi, P. (May 3, 2004). "Effects of Periodic Inflow Unsteadiness on the Time-Averaged Velocity Field and Pressure Recovery of a Diffusing Bend With Strong Curvature ." ASME. J. Fluids Eng. March 2004; 126(2): 229–237. https://doi.org/10.1115/1.1667887
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