Effects of area ratio and mean rise angle on the aerodynamics of inter-turbine ducts

DOIResolve DOI: http://doi.org/10.1115/GT2014-27207
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Proceedings titleProceedings of the ASME Turbo Expo
ConferenceASME Turbo Expo 2014: Turbine Technical Conference and Exposition, GT 2014, 16 June 2014 through 20 June 2014
SubjectAerodynamics; Boundary layer flow; Pressure gradient; Reynolds number; Turbines; Vortex flow; Adverse pressure gradient; Boundary-layer separation; Computational studies; Counter-rotating vortices; Pressure loss; Static pressure; Upstream wake; Ducts
AbstractThe present work, a continuation of a series of investigations on the aerodynamics of aggressive inter-turbine ducts (ITD), is aimed at providing detailed understanding of the flow physics and loss mechanisms in four different ITD geometries. A systematic experimental and computational study was carried out for varying duct mean rise angles and outlet-toinlet area ratio while keeping the duct length-to-inlet height ratio, Reynolds number and inlet swirl constant in all four geometries. The flow structures within the ITDs were found to be dominated by the counter-rotating vortices and boundary layer separation in both the casing and hub regions. The duct mean rise angle determined the severity of adverse pressure gradient in the casing's first bend whereas the duct area ratio mainly governed the second bend's static pressure rise. The combination of upstream wake flow and the first bend's adverse pressure gradient caused the boundary layer to separate and intensify the strength of counter-rotating vortices. At high mean rise angle, the separation became stronger at the casing's first bend and moved farther upstream. At high area ratios, a 2-D separation appeared on the casing. Pressure loss penalties increased significantly with increasing duct mean rise angle and area ratio.
Publication date
PublisherAmerican Society of Mechanical Engineers
AffiliationNational Research Council Canada; NRC Institute for Aerospace Research; Aerospace
Peer reviewedYes
NPARC number21275616
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Record identifier7665e5dd-44e8-41bd-b8bb-1f64dc3b0d69
Record created2015-07-14
Record modified2016-05-09
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