0
Research Papers

Effect of Impeller Blade Loading on Compressor Stage Performance in a High Specific Speed Range

[+] Author and Article Information
Takanori Shibata

Energy and Environmental Systems Laboratory, Hitachi, Ltd., 2-1, Omika-cho, 7-chome, Hitachi-shi, Ibaraki 319-1221, Japantakanori.shibata.by@hitachi.com

Manabu Yagi

Energy and Environmental Systems Laboratory, Hitachi, Ltd., 2-1, Omika-cho, 7-chome, Hitachi-shi, Ibaraki 319-1221, Japan

Hideo Nishida, Hiromi Kobayashi, Masanori Tanaka

Tsuchiura Research Laboratory, Hitachi Plant Technologies, Ltd., 603 Kandatsu-machi, Tsuchiura-shi, Ibaraki 300-0013, Japan

J. Turbomach 134(4), 041012 (Jul 21, 2011) (9 pages) doi:10.1115/1.4003659 History: Received October 11, 2010; Revised January 12, 2011; Published July 21, 2011; Online July 21, 2011

The authors previously found that compressor stage efficiency in a high specific speed range was significantly improved by employing an increased relative velocity diffusion ratio coupled with a high backsweep angle (Shibata, “Performance Improvement of a Centrifugal Compressor Stage by Increasing Degree of Reaction Optimizing Blade Loading of a 3D-Impeller,” ASME Paper No. GT2009-59588). In spite of such a high relative velocity diffusion ratio, the same surge margin as with a conventional design was able to be achieved by using a special front loading distribution with a lightly loaded inducer. In the present study, the blade loading distribution was further optimized in order to achieve a larger surge margin than previously. Four types of fully shrouded impellers were designed, manufactured, and tested to evaluate the effects of blade loading, backsweep angle, and relative velocity diffusion ratio on compressor performance. The design suction flow coefficient was 0.125 and the machine Mach number was 0.87. Test results showed that the developed impeller achieved 3.8% higher stage efficiency and 11% larger surge margin than the conventional design without reducing the pressure coefficient and choke margin. It was concluded that aft loading coupled with a high degree of reaction was a very effective way to improve surge margin as well as stage efficiency. Stator matching was also investigated by changing the design incidence angle, which was shown to have a little influence on surge margin in the present test results.

Copyright © 2012 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Measured performance characteristics of FL_B (ribbed) and BL (ribbed)

Grahic Jump Location
Figure 2

Blade trimming for the FL impeller

Grahic Jump Location
Figure 3

Blade loading distributions on the shroud side

Grahic Jump Location
Figure 4

Test results of the effect of W1s/W2 on the operating range of FL and ML impellers (ribbed)

Grahic Jump Location
Figure 5

Blade loading and blade angle distributions on the shroud side

Grahic Jump Location
Figure 6

Relative velocity distributions on the shroud side

Grahic Jump Location
Figure 7

Comparison of meridional sections between developed and conventional impellers

Grahic Jump Location
Figure 8

Blade loading effects on the impeller characteristic curves obtained using CFD

Grahic Jump Location
Figure 9

Calculated flow patterns near the surge point for the AL′ and FL′ impellers

Grahic Jump Location
Figure 10

Compressor test apparatus

Grahic Jump Location
Figure 11

Model compressor test section

Grahic Jump Location
Figure 12

Measured performance characteristics of AL′ and BL′ impellers

Grahic Jump Location
Figure 13

Measured performance characteristics of AL′, ML, and FL′ impellers

Grahic Jump Location
Figure 14

Relation between efficiency and relative velocity diffusion ratio W1s/W2 at the spec flow rate

Grahic Jump Location
Figure 15

Relation between surge margin and relative velocity diffusion ratio W1s/W2 at the spec flow rate

Grahic Jump Location
Figure 16

Effect of stator matching on stage performance for the AL′ impeller

Grahic Jump Location
Figure 17

Effect of full-shrouding on stage performance of the FL′ impeller

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
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