Please use this identifier to cite or link to this item: https://hdl.handle.net/11264/1021
Title: Measurement and Computation of Losses from a Transonic Turbine Vane Cascade
Authors: Andrews, Stephen Arthur
Royal Military College of Canada / Collège militaire royal du Canada
Allan, William D. E.
Mahallati, Ali
Keywords: Gas Turbine
Aerodynamics
Transonic
Issue Date: 23-Jun-2016
Abstract: Experimental and numerical studies were performed on a cascade of first stage nozzle guide vanes operating at transonic speeds. Detailed pressure measurements on the blade surface and in the wake, as well as oil film and schlieren flow visualization were combined with computational predictions to examine the aerodynamic performance of the blades. Experimental data were collected between Mach 0.3 and 1.3, while computational predictions extended this range to Mach 1.7. The analysis was focused on examining the behaviour of the blade losses with increasing Mach number. The losses reached a local maximum at an exit Mach number of unity and experienced a subsequent decrease or plateau with increasing Mach number. The computational results showed that this transonic loss plateau existed until the exit Mach number exceeded 1.4. Investigations into the aerodynamic performance of the blade showed that the base pressure had a strong influence on the behaviour of the losses. At supersonic speeds, shocks and shock-boundary layer interactions were also important contributors to the loss. Steady and unsteady computational models showed excellent qualitative and fair quantitative agreement with the experimental data. Empirical correlations for the losses under-predicted the experimental measurements. The behaviour of the aerodynamic losses from the nozzle guide vane under investigation showed that there was a potential advantage, or at least no penalty, to operating at exit Mach numbers higher than the design value of 1.16. If the mating rotor could tolerate the increased inlet speed, this could result in an increase in stage efficiency.
L'analyse se concentra sur la correlation des pertes en fonction du nombre de Mach Croissant. Les pertes ont atteint un maximum at un nombre de Mach unitaire à la sortie et dépendamment de la définition de perte employée, montre une diminution suivie d'un plateau à mesure que le nombre de Mach augmente. Les résultats numériques démontrent que le plateau s'étend jusqu'à Mach 1.4 L'étude de la performance aérodynamique de l'aube montre que la pression du culot a une forte influence sur les pertes. Aux vitesses supersoniques, l'interaction entre les ondes de choc et la couche limite contribue aussi grandement aux pertes. Les pertes engendrées dans la couche limite non décollé ont très peu d'effets sur la performance de l'aube. Les modèlles numériques, stationnaire et instationnaire, montrent un excellent accord qualitatif et une bonne représentation quantitative des données expérimentales. Les corrélations empiriques pour les pertes sous-estiment les valeurs expérimentales. La perte aérodynamique résultant des aubes étudiées montre qu'il y a un avantage ou du moins aucun dèsavantage à utiliser ces aubes à des nombres de Mach à la sortie plus grandes que celle de conception soit 1.16. Si le rotor couplé a ce stator peut accepter cette vitesse accrée, ceci pourrait accroïtre le rendement de l'étage.
URI: https://hdl.handle.net/11264/1021
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