Proceedings ArticleDOI
Aerodynamic Tip Desensitization of an Axial Turbine Rotor Using Tip Platform Extensions
Debashis Dey,Cengiz Camci +1 more
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TLDR
In this paper, the authors used the concept of a tip platform extension that is a very short "winglet" obtained by slightly extending the tip platform in the tangential direction.Abstract:
Aerodynamic losses due to the formation of a leakage vortex near the tip section of rotor blades form a significant part of viscous losses in axial flow turbines. The leakage flow, mainly induced by the pressure differential between the pressure side and suction side of a rotor tip section, usually rolls into a streamwise vortical structure near the suction side part of the blade tip. The current study uses the concept of a tip platform extension that is a very short “winglet” obtained by slightly extending the tip platform in the tangential direction. The use of a pressure side tip extension can significantly affect the local aerodynamic field by weakening the leakage vortex structure. Phase averaged, time accurate total pressure measurements downstream of a single stage turbine facility are provided from a total pressure probe that has a time response of 150 kHz. Complete total pressure maps in all of the 29 rotor exit planes are measured accurately. Various pressure and suction side extension configurations are compared against a baseline case. The current investigation performed in the Axial Flow Turbine Research Facility (AFTRF) of the Pennsylvania State University shows that significant total to total efficiency gain is possible by the use of tip platform extensions.Copyright © 2001 by ASMEread more
Citations
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Journal ArticleDOI
Aerodynamics of Tip Leakage Flows Near Partial Squealer Rims in an Axial Flow Turbine Stage
TL;DR: In this paper, the aerodynamic characteristics of full and partial-length squealer rims in a turbine stage were investigated separately on the pressure side and on the suction side in the Axial Flow Turbine Research Facility (AFTRF) of the Pennsylvania State University.
Journal ArticleDOI
Aero-Thermal Performance of a Winglet at Engine Representative Mach and Reynolds Numbers
D. O. O’Dowd,Qiang Zhang,Li He,M. L. G. Oldfield,P. M. Ligrani,Brian C. Y. Cheong,Ian Tibbott +6 more
TL;DR: In this paper, an experimental investigation of the aero-thermal performance of a cooled winglet tip, under transonic conditions (exit Mach number 1.0, and an exit Reynolds number of 1.27×106, based on axial chord), is presented.
Journal ArticleDOI
Effects of turbine blade tip shape on total pressure loss and secondary flow of a linear turbine cascade
TL;DR: In this paper, the effects of tip shape on the secondary flow and total pressure loss in a turbine cascade have been investigated experimentally and a total of 11 tip shapes including plane, single or double squealer, dimpled, chamfered, and grooved tips were tested.
Journal ArticleDOI
A review of cavitation in tip-leakage flow and its control
TL;DR: In this article, the authors reviewed the progress in the researches of the tip-leakage vortex (TLV) cavitation, including the numerical methods for the TLV cavitation and the flow characteristics.
Journal ArticleDOI
Overtip Choking and Its Implications on Turbine Blade-Tip Aerodynamic Performance
Qiang Zhang,Li He +1 more
TL;DR: In this article, a high speed linear cascade validation case is introduced, and the computations are compared with the experimental data to identify and establish the capability of the code in predicting the aerodynamics losses for a transonic turbine blade tip.
References
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Proceedings ArticleDOI
Loss Mechanisms in Turbomachines
TL;DR: The origins and effects of loss in turbomachines are discussed in this article with the emphasis on trying to understand the physical origins of loss rather than on reviewing the available prediction methods.
Journal ArticleDOI
Recent Progress in the Understanding of Basic Aspects of Secondary Flows in Turbine Blade Passages
TL;DR: In this paper, the authors describe tourbillonnaires de l'ecoulement secondaire and leur influence on les caracteristiques de couche limite a la paroi d'extremite, including the origin, croissance, and distribution spatiale des pertes dans des passages d'aubes de turbine.
Journal ArticleDOI
Secondary Flows in Axial Turbines—A Review
TL;DR: It is concluded that accurate routine prediction of secondary flow losses has not yet been achieved, and must await either a better turbulence model or more experiments to reveal new endwall loss production mechanisms.
Journal ArticleDOI
Rotor-Tip Leakage: Part I—Basic Methodology
TL;DR: In this paper, a simple tip-leakage model is proposed that treats the normal velocity component in terms of discharge coefficient and conserves the tangential velocity (momentum) component.
Journal ArticleDOI
Tip clearance effects in a turbine rotor : Part I : Pressure field and loss
TL;DR: In this paper, the authors investigated the effects of the tip clearance flow in an axial turbine rotor, including the distribution and the development of the pressure, the loss, the velocity, and the turbulence fields.
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