Some Experiences About the Impact of Unsteadiness in Turbine Flows

TitleSome Experiences About the Impact of Unsteadiness in Turbine Flows
Publication TypeConference Paper
Year of Publication2015
AuthorsBellucci J, Rubechini F, Arnone A
Conference NameASME Turbo Expo 2015: Turbine Technical Conference and Exposition
Date PublishedJune 15–19
Conference LocationMontreal, Canada
ISBN Number978-079185663-5
Accession NumberWOS:000380084400069
Other NumbersScopus 2-s2.0-84954357361

This paper discusses the role of the unsteady interaction in turbine design. It focuses on aerodynamic performance, and its main motivation consists in trying to identify some design areas in which some further margins of improvement could be found, provided the designer chooses the proper computational framework. The underlying idea is that the approximations associated with the steady-state picture of a turbine stage might prevent from unlocking the full potential of the stage itself, especially when the design requirements imply a challenging aerodynamics. To this end, three common design topics are presented in which the step from the classical steady-state approach to the time-accurate one unveils relevant issues, which in turn have a relapse on aerodynamic performance: stator/rotor interaction in transonic stages, the choice of the axial gap between stator and rotor, and the choice of the blade count ratio. In all reported cases, significant departures are found between steady and time-averaged results, and the basic fluid mechanisms responsible for them are examined. In particular, an attempt is made to emphasize limitations deriving from of the steady-state picture of the turbine flow field, in order to warn the designer about the possible traps of the steady-state assumption.



ASME paper GT2015-43122 

Refereed DesignationRefereed