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

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21220%2F18%3A00324417" target="_blank" >RIV/68407700:21220/18:00324417 - isvavai.cz</a>

Výsledek na webu

<a href="http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2701061" target="_blank" >http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2701061</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1115/GT2018-76567" target="_blank" >10.1115/GT2018-76567</a>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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.

Druh

D - Stať ve sborníku

CEP obor

—

OECD FORD obor

20304 - Aerospace engineering

Projekt

—

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2018

Kód důvěrnosti údajů

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

Název statě ve sborníku

ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition, Volume 5B: Heat Transfer

ISBN

978-0-7918-5109-8

ISSN

—

e-ISSN

—

Počet stran výsledku

15

Strana od-do

—

Název nakladatele

American Society of Mechanical Engineers - ASME

Místo vydání

New York

Místo konání akce

Lillestrom

Datum konání akce

11. 6. 2018

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

—