Entropy generation measurement in a laminar turbine blade boundary-layer

John D. Wallace, Mark R.D. Davies

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

This paper demonstrates a method of calculating the entropy generation rate in an incompressible laminar turbine blade boundary-layer from measurements of surface heat transfer rate. It is shown that the entropy generated by fluid friction in an incompressible blade boundary-layer is significantly less than that generated by heat transfer at engine representative temperature ratios. The centre blade in a lowspeed linear cascade is electrically heated and isolated from the airflow with a bypass valve. Upon opening the valve the blade is transiently cooled and thin film heat transfer gauges, painted on machinable glass ceramic inserts mounted into the surface of the blade, are used to record blade surface temperature and surface heat transfer rate signals; local Nusselt numbers are then calculated. Non-dimensional temperature distributions are derived across the boundary-layer using the blade surface heat transfer rate and a similarity condition. The equation describing the local entropy generation per unit volume is then integrated through the boundary-layer at each chordwise measurement point on the blade surface.

Original languageEnglish
Title of host publicationAircraft Engine; Marine; Turbomachinery; Microturbines and Small Turbomachinery
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791878682
DOIs
Publication statusPublished - 1997
EventASME 1997 International Gas Turbine and Aeroengine Congress and Exhibition, GT 1997 - Orlando, United States
Duration: 2 Jun 19975 Jun 1997

Publication series

NameProceedings of the ASME Turbo Expo
Volume1

Conference

ConferenceASME 1997 International Gas Turbine and Aeroengine Congress and Exhibition, GT 1997
Country/TerritoryUnited States
CityOrlando
Period2/06/975/06/97

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