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Endwall loss in turbine cascades

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Coull, JD 

Abstract

jats:pPrior to the detailed design of components, turbomachinery engineers must guide a mean-line or throughflow design toward an optimum configuration. This process requires a combination of informed judgement and low-order correlations for the principle sources of loss. With these requirements in mind, this paper examines the impact of key design parameters on endwall loss in turbines, a problem which remains poorly understood. This paper presents a parametric study of linear cascades, which represent a simplified model of real-engine flow. The designs are nominally representative of the low-pressure turbine blades of an aero-engine, with varying flow angles, blade thickness, and suction surface lift styles. Reynolds-averaged Navier–Stokes (RANS) calculations are performed for a single aspect ratio (AR) and constant inlet boundary layer thickness. To characterize the cascades studied, the two-dimensional design space is examined before studying endwall losses in detail. It is demonstrated that endwall loss can be decomposed into two components: one due to the dissipation associated with the endwall boundary layer and another induced by the secondary flows. This secondary-flow-induced loss is found to scale with a measure of streamwise vorticity predicted by classical secondary flow theory.</jats:p>

Description

Keywords

4012 Fluid Mechanics and Thermal Engineering, 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
Rolls-Royce plc