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CLOCKING IN LOW-PRESSURE TURBINES

Published version
Peer-reviewed

Change log

Authors

Evans, KR 
Longley, JP 

Abstract

jats:pThe effect of stator clocking has been experimentally and computationally investigated using a low-speed, two-stage, Low-Pressure Turbine which was specifically designed to maximise the clocking potential by aligning the Stator 1 wake segments with the Stator 2 leading edge along the span. It was verified that the wake segments are aligned to within 10% of stator pitch across the span. The measured clocking effect on the work extraction is 0.12% and on efficiency is 0.08%. Although the effect of clocking is small, it is repeatable, periodic across four stator pitches and consistent between independent measurements. Furthermore, factors to consider for a reliable clocking investigation are discussed.</jats:p> jats:pThe measurements revealed that the majority of the clocking effect on the work extraction occurs in Stage 2 and it originates at Stator 2 exit. This indicates that the flow is being processed differently within Stator 2. There is also an effect on the Stage 1 work. In each blade row the measured clocking effect on the lost work is similar across the span.</jats:p> jats:pThe computations with meshed cavities do not capture any clocking effects in Stage 1. This indicates that an unsteady viscid phenomenon within Rotor 1 is not captured by the fully turbulent calculation e.g. unsteady transition. However, the computations do capture the measured clocking effect on the Stage 2 work extraction.</jats:p> jats:pIt is hypothesised that the clocking effect on Stator 2 flow turning is dominated by a steady, inviscid process.</jats:p>

Description

Keywords

4012 Fluid Mechanics and Thermal Engineering, 40 Engineering, 7 Affordable and Clean Energy

Journal Title

PROCEEDINGS OF THE ASME TURBO EXPO: TURBINE TECHNICAL CONFERENCE AND EXPOSITION, 2016, VOL 2B

Conference Name

ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition

Journal ISSN

Volume Title

2B: Turbomachinery

Publisher

American Society of Mechanical Engineers
Sponsorship
The authors are grateful to Rolls-Royce plc who supported this work through a TSB SAMULET research grant and for their permission to publish.