0
Journal of Turbomachinery | Volume 131 | Issue 4 | Research Paper
Research Papers

Effect of Unsteadiness on the Performance of a Transonic Centrifugal Compressor Stage

[+] Author and Article Information
Isabelle Trébinjac, Pascale Kulisa, Nicolas Bulot

Laboratoire de Mécanique des Fluides et d’Acoustique, UMR CNRS 5509, Ecole Centrale de Lyon, UCBLyon I, INSA 36 Avenue Guy de Collongue, 69134 Ecully Cedex, France

Nicolas Rochuon

TURBOMECA, Groupe SAFRAN, 64511 Bordes, France

J. Turbomach 131(4), 041011 (Jul 02, 2009) (9 pages) doi:10.1115/1.3070575 History: Received August 21, 2008; Revised September 10, 2008; Published July 02, 2009
Article
References
Figures
Citing Articles

Numerical and experimental investigations were conducted in a transonic centrifugal compressor stage composed of a backswept splittered unshrouded impeller and a vaned diffuser. The characteristic curves of the compressor stage resulting from the unsteady simulations and the experiments show a good agreement over the whole operating range. On the contrary, the total pressure ratio resulting from the steady simulations is clearly overestimated. A detailed analysis of the flow field at design operating point led to identify the physical mechanisms involved in the blade row interaction that underlie the observed shift in performance. Attention was focused on the deformation in shape of the vane bow shock wave due its interaction with the jet and wake flow structure emerging from the impeller. An analytical model is proposed to quantify the time-averaged effects of the associated entropy increase. The model is based on the calculation of the losses across a shock wave at various inlet Mach numbers corresponding to the moving of the jet and wake flow in front of the shock wave. The model was applied to the compressor stage performance calculated with the steady simulations. The resulting curve of the overall pressure ratio as a function of the mass flow is clearly shifted toward the unsteady results. The model, in particular, enhances the prediction of the choked mass flow.
FIGURES IN THIS ARTICLE
<>
Copyright © 2009 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
+3D sketch of the centrifugal compressor stage
View Large  |  Save Figure  |  Download Slide (.ppt)
3D sketch of the centrifugal compressor stage
Figure 1

3D sketch of the centrifugal compressor stage

Grahic Jump Location
+Meridional view of the compressor stage
View Large  |  Save Figure  |  Download Slide (.ppt)
Meridional view of the compressor stage
Figure 2

Meridional view of the compressor stage

Grahic Jump Location
+H-C-O topology of the mesh
View Large  |  Save Figure  |  Download Slide (.ppt)
H-C-O topology of the mesh
Figure 3

H-C-O topology of the mesh

Grahic Jump Location
+Pressure ratio of the compressor stage
View Large  |  Save Figure  |  Download Slide (.ppt)
Pressure ratio of the compressor stage
Figure 4

Pressure ratio of the compressor stage

Grahic Jump Location
+Reduced temperature rise
View Large  |  Save Figure  |  Download Slide (.ppt)
Reduced temperature rise
Figure 5

Reduced temperature rise

Grahic Jump Location
+Level of unsteadiness through the impeller (a) and through the vaned diffuser (b)
View Large  |  Save Figure  |  Download Slide (.ppt)
Level of unsteadiness through the impeller (a) and through the vaned diffuser (b)
Figure 6

Level of unsteadiness through the impeller (a) and through the vaned diffuser (b)

Grahic Jump Location
+Reduced meridional velocity at section E (m∗=0.63)
View Large  |  Save Figure  |  Download Slide (.ppt)
Reduced meridional velocity at section E (m∗=0.63)
Figure 7

Reduced meridional velocity at section E (m∗=0.63)

Grahic Jump Location
+Reduced tangential velocity at section E (m∗=0.63)
View Large  |  Save Figure  |  Download Slide (.ppt)
Reduced tangential velocity at section E (m∗=0.63)
Figure 8

Reduced tangential velocity at section E (m∗=0.63)

Grahic Jump Location
+Purely unsteady relative velocity at mid inter-row gap and 70% section height, over a stator pitch and a rotor time-period
View Large  |  Save Figure  |  Download Slide (.ppt)
Purely unsteady relative velocity at mid inter-row gap and 70% section height, over a stator pitch and a rotor time-period
Figure 9

Purely unsteady relative velocity at mid inter-row gap and 70% section height, over a stator pitch and a rotor time-period

Grahic Jump Location
+Meridional evolution of entropy
View Large  |  Save Figure  |  Download Slide (.ppt)
Meridional evolution of entropy
Figure 10

Meridional evolution of entropy

Grahic Jump Location
+Absolute Mach number contours, at 50% section height
View Large  |  Save Figure  |  Download Slide (.ppt)
Absolute Mach number contours, at 50% section height
Figure 11

Absolute Mach number contours, at 50% section height

Grahic Jump Location
+Absolute Mach number, at 50% height
View Large  |  Save Figure  |  Download Slide (.ppt)
Absolute Mach number, at 50% height
Figure 12

Absolute Mach number, at 50% height

Grahic Jump Location
+Absolute normal Mach number, close to impeller exit
View Large  |  Save Figure  |  Download Slide (.ppt)
Absolute normal Mach number, close to impeller exit
Figure 13

Absolute normal Mach number, close to impeller exit

Grahic Jump Location
+Corrected pressure ratio of the compressor stage
View Large  |  Save Figure  |  Download Slide (.ppt)
Corrected pressure ratio of the compressor stage
Figure 14

Corrected pressure ratio of the compressor stage

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Control and Operational Performance
Closed-Cycle Gas Turbines> Chapter 5
Other Components and Variations
Axial-Flow Compressors> Chapter 13
Thermodynamic Performance
Closed-Cycle Gas Turbines> Chapter 6
Outlook
Closed-Cycle Gas Turbines> Chapter 11
Aerodynamic Performance Analysis
Axial-Flow Compressors> Chapter 9
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In