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Design of Compressor Endwall Velocity Triangles

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Auchoybur, Kiran 
Miller, Robert J 

Abstract

jats:pThe operating range of a compressor is usually limited by the rapid growth of three-dimensional (3D) separations in the endwall flow region. In contrast, the freestream region is not usually close to its diffusion limit and has little effect on overall range. In light of these two distinct flow regions, this paper considers how velocity triangles in the endwall region should be designed to give a more balanced spanwise failure across the span of a blade row. In the first part of this paper, the sensitivity of 3D separations in a single blade row to variations in realistic multistage inlet conditions and endwall geometry is investigated. It is shown that a blade's 3D separation size is largely controlled by the dynamic pressure within the incoming endwall “repeating stage” boundary layer and not the detailed local geometry within the blade row. In the second part of this paper, the traditional design process is “flipped.” Instead of redesigning a blade's endwall geometry to cope with a particular inlet profile into the blade row, the endwall region is redesigned in the multistage environment to “tailor” the inlet profile into downstream blade rows, giving the designer a new extra degree-of-freedom. This extra degree-of-freedom is exploited to balance freestream and endwall operating range, resulting in a compressor having an increased operating range of ∼20%. If this increased operating range is traded with reduced blade count, it is shown that a design efficiency improvement of ∼0.5% can be unlocked.</jats:p>

Description

Keywords

40 Engineering, 4001 Aerospace Engineering

Journal Title

Journal of Turbomachinery

Conference Name

Journal ISSN

0889-504X
1528-8900

Volume Title

139

Publisher

ASME International
Sponsorship
European Commission (283216)
EPSRC (EP/K503757/1)