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Experimental Investigation of Turbine Leakage Flows on the Three-Dimensional Flow Field and Endwall Heat Transfer

Rehder, Hans-Jürgen and Dannhauer, Axel (2007) Experimental Investigation of Turbine Leakage Flows on the Three-Dimensional Flow Field and Endwall Heat Transfer. Journal of Turbomachinery, 129 (4), pp. 608-618.

Full text not available from this repository.

Abstract

Within a European research project the tip endwall region of low pressure turbine guide vanes with leakage ejection was investigated at DLR in Göttingen. For this purpose a new cascade wind tunnel with three large profiles in the test section and a contoured endwall was designed and built up, representing 50% height of a real low pressure turbine stator and simulating the casing flow field of shrouded vanes. The effect of tip leakage flow was simulated by blowing air through a small leakage gap in the endwall just upstream of the vane leading edges. Engine relevant turbulence intensities were adjusted by an active turbulence generator mounted in the test section inlet plane. The experiments were performed with tangential and perpendicular leakage ejection and varying leakage mass flow rates up to 2%. Aerodynamic and thermodynamic measurement techniques were employed. Pressure distribution measurements provided information about the endwall and vane surface pressure field and its variation with leakage flow. Additionally streamline pattern (local shear stress directions) on the walls were detected by oil flow visualization. Downstream traverses with five-hole pyramid type probes allow a survey of the secondary flow behavior in the cascade exit plane. The flow field in the near endwall area downstream of the leakage gap and around the vane leading edges was investigated using a 2D Particle Image Velocimetry system. In order to determine endwall heat transfer distributions, the wall temperatures were measured by an infrared camera system, while heat fluxes at the surfaces were generated with electric operating heating foils. It turned out from the experiments that distinct changes in the secondary flow behavior and endwall heat transfer mainly occur when the leakage mass flow rate is increased from 1% to 2%. Leakage ejection perpendicular to the main flow direction amplifies the secondary flow, in particular the horse-shoe vortex, whereas tangential leakage ejection causes a significant reduction of this vortex system. For high leakage mass flow rates the boundary layer flow at the endwall is strongly affected and seems to be highly turbulent, resulting in entirely different heat transfer distributions.

Item URL in elib:https://elib.dlr.de/51207/
Document Type:Article
Title:Experimental Investigation of Turbine Leakage Flows on the Three-Dimensional Flow Field and Endwall Heat Transfer
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Rehder, Hans-JürgenUNSPECIFIEDUNSPECIFIED
Dannhauer, AxelUNSPECIFIEDUNSPECIFIED
Date:July 2007
Journal or Publication Title:Journal of Turbomachinery
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:Yes
Volume:129
Page Range:pp. 608-618
Editors:
EditorsEmail
ASME, UNSPECIFIED
Status:Published
Keywords:shrouded turbine vane, tip leakage gap, leakage ejection, secondary flow field, endwall heat transfer
HGF - Research field:other
HGF - Program:Aeronautics
HGF - Program Themes:Propulsion Systems (old)
DLR - Research area:Aeronautics
DLR - Program:L ER - Engine Research
DLR - Research theme (Project):L - Turbine Technologies (old)
Location: Göttingen
Institutes and Institutions:Institute of Propulsion Technology > Turbine
Deposited By: Klein, Stephanie
Deposited On:04 Sep 2007
Last Modified:27 Apr 2009 14:20

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