Redesign of High-Lift Low Pressure Turbine Airfoils For Low Speed Testing

TitleRedesign of High-Lift Low Pressure Turbine Airfoils For Low Speed Testing
Publication TypeJournal Article
Year of Publication2012
AuthorsMarconcini M, Rubechini F, Pacciani R, Arnone A, Bertini F
JournalASME Journal of Turbomachinery
Date Published09/2012
ISSN Number0889-504X
Accession NumberWOS:000308404500017
Other NumbersScopus 2-s2.0-84861118159
KeywordsHigh Lift, LKE, Low Speed, LPT, Separated Flow Transition

Low pressure turbine airfoils of the present generation usually operate at subsonic conditions, with exit Mach numbers of about 0.6. To reduce the costs of experimental programs it can be convenient to carry out measurements in low speed tunnels in order to determine the cascades performance. Generally speaking, low speed tests are usually carried out on airfoils with modified shape, in order to compensate for the effects of compressibility. A scaling procedure for high-lift, low pressure turbine airfoils to be studied in low speed conditions is presented and discussed. The proposed procedure is based on the matching of a prescribed blade load distribution between the low speed airfoil and the actual one. Such a requirement is fulfilled via an Artificial Neural Network (ANN) methodology and a detailed parameterization of the airfoil. A RANS solver is used to guide the redesign process. The comparison between high and low speed profiles is carried out, over a wide range of Reynolds numbers, by using a novel three-equation, transition-sensitive, turbulence model. Such a model is based on the coupling of an additional transport equation for the so-called laminar kinetic energy (LKE) with the Wilcox k-omega model and it has proven to be effective for transitional, separated-flow configurations of high-lift cascade flows.

Original PublicationASME paper GT2010-23284
Refereed DesignationRefereed