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Separation and relaminization at the circular arc leading edge of a controlled diffusion compressor stator

Citation

Perkins, SCT and Henderson, AD, Separation and relaminization at the circular arc leading edge of a controlled diffusion compressor stator, Proceedings of ASME Turbo Expo 2012, 11-15 June, Copenhagen, Denmark, pp. 69384.1-12. ISBN 9780791844670 (2012) [Refereed Conference Paper]

Copyright Statement

Copyright 2012 ASME

Official URL: https://www.asme.org

Abstract

This paper investigates the influence of Reynolds Number and incidence on boundary layer development at the leading edge of a controlled diffusion (CD) stator blade with circular arc leading edge profile. Steady flow measurements were made inside a large scale 2D compressor cascade at Reynolds numbers of 260,000 and 400,000 for a range of inlet flow angles corresponding to both positive and negative incidence. Detailed static pressure measurements in the leading edge region show the time-mean boundary layer development through the velocity overspeed and following region of accelerating flow on the suction surface. Separation bubbles at the leading edge of the pressure and suction surfaces trigger the boundary layer to undergo an initial and rapid transition to turbulence. On the pressure surface, the bubble forms at all values of incidence tested, whereas on the suction surface a bubble only forms for incidence greater than design. In all cases the bubble length was seen to reduce significantly as Reynolds number is increased. These trends are supported by surface flow visualization results. Quasiwall shear stress measurements from hot-film sensors were interpreted using a hybrid threshold peak-valley-counting algorithm to yield time-averaged turbulent intermittency on each blade surface. These results in combination with raw quasi-wall shear stress traces show evidence of boundary layer relaminarization on the suction surface, downstream of the leading edge velocity overspeed in the favorable pressure gradient leading to peak suction. The relaminarization process is observed to become less effective as Reynolds number and inlet flow angle are increased. The boundary layer development is shown to have a large influence on the total blade pressure loss. At negative incidence, loss was seen to increase as Reynolds number is decreased, and in contrast at positive incidence, the opposite trend was displayed.

Item Details

Item Type:Refereed Conference Paper
Keywords:axial, compressor, leading edge
Research Division:Engineering
Research Group:Mechanical Engineering
Research Field:Energy Generation, Conversion and Storage Engineering
Objective Division:Energy
Objective Group:Energy Transformation
Objective Field:Energy Transformation not elsewhere classified
Author:Perkins, SCT (Mr Sam Perkins)
Author:Henderson, AD (Dr Alan Henderson)
ID Code:82689
Year Published:2012
Deposited By:Engineering
Deposited On:2013-02-12
Last Modified:2014-08-13
Downloads:0

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