Experimental and Numerical Investigation of Optimized Blade Tip Shapes: Part II — Tip Flow Analysis and Loss Mechanisms

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21220%2F18%3A00324786" target="_blank" >RIV/68407700:21220/18:00324786 - isvavai.cz</a>

Result on the web

<a href="http://turbomachinery.asmedigitalcollection.asme.org/article.aspx?articleid=2703056" target="_blank" >http://turbomachinery.asmedigitalcollection.asme.org/article.aspx?articleid=2703056</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1115/1.4041466" target="_blank" >10.1115/1.4041466</a>

Result language

angličtina

Original language name

Experimental and Numerical Investigation of Optimized Blade Tip Shapes: Part II — Tip Flow Analysis and Loss Mechanisms

Original language description

A comprehensive study is presented in this two-part paper that investigates the influence of blade tip geometry on the aerother-modynamics of a high-speed turbine. An experimental and numerical campaign has been performed on a high-pressure turbine stage adopting three different blade tip profiles. The aerothermal performance of two optimized tip geometries (one with a full three-dimensional contoured shape and the other featuring a multi-cavity squealer-like tip) is compared against that of a regular squealer geometry. In the second part of this paper, we report a detailed analysis on the aerodynamics of the turbine as a function of the blade tip geometry. Reynolds-averaged Navier-Stokes simulations, adopting the Spalart-Allmaras turbulence model and experimental boundary conditions, were run on high-density unstructured meshes using the Numeca FINE/Open solver. The simulations were validated against time-averaged and time-resolved experimental data collected in an instrumented turbine stage specifically set up for the simultaneous testing of multiple blade tips at scaled engine-representative conditions. The tip flow physics is explored to explain variations in turbine performance as a function of the tip geometry. Denton’s mixing loss model is applied to the predicted tip gap aerodynamic field to identify and quantify the loss reduction mechanisms of the alternative tip designs. An advanced method based on the local triple decomposition of relative motion is used to track the location, size and intensity of the vortical flow structures arising from the interaction between the tip leakage flow and the main gas path. Ultimately, the comparison between the unconventional tip profiles and the baseline squealer tip highlights distinct aerodynamic features in the associated gap flow field. The flow analysis provides guidelines for the designer to assess the impact of specific tip design strategies on the turbine aerodynamics and rotor heat transfer.

Czech name

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Czech description

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Type

J_ost - Miscellaneous article in a specialist periodical

CEP classification

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OECD FORD branch

20304 - Aerospace engineering

Project

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Continuities

S - Specificky vyzkum na vysokych skolach

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Journal of Turbomachinery

ISSN

0889-504X

e-ISSN

1528-8900

Volume of the periodical

141

Issue of the periodical within the volume

1

Country of publishing house

US - UNITED STATES

Number of pages

13

Pages from-to

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UT code for WoS article

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EID of the result in the Scopus database

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