Publications

Aerodynamic Design of High End Wall Angle Turbine Stages—Part II: Experimental Verification

Authors:

A. W. Cranstone; G. Pullan; E. M. Curtis; S. Bather

Publication:

J. Turbomach. 2013; 136(2):021007-021007-10.

DOI:

10.1115/1.4023906

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Effect of Cooling Injection on Transonic Tip Flows

In this paper, the effect of cooling injection on the aerodynamics of tip flows in transonic turbines is investigated. Experiments are performed using an idealized model of a transonic tip flow. Schlieren photography, probe, and surface pressure measurements are used to determine the transonic tip flow structure and to validate the computational method. Computational simulations are performed to investigate the effects of cooling injection in a transonic blade environment. The results show that cooling injection has the potential to reduce overtip leakage loss.

Authors:

Andrew P. S. Wheeler, Zainab Saleh

Publication:

Journal of Propulsion and Power

DOI:

10.2514/1.B34657

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Influence of Film Cooling Hole Angles and Geometries on Aerodynamic Loss and Net Heat Flux Reduction

Authors:

Chia Hui Lim; Graham Pullan; Peter Ireland

Publication:

J. Turbomach. 2013; 135(5):051019-051019-13.

DOI:

10.1115/1.4023088

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Improving Intermediate Pressure Turbine Performance by Using a Nonorthogonal Stator

Authors:

Sungho Yoon; John Denton; Eric Curtis; John Longley; Graham Pullan

Publication:

J. Turbomach. 2013; 136(2):021012-021012-8.

DOI:

10.1115/1.4023941

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Experimental investigation into the impact of crossflow on the coherent unsteadiness within film coo

he current paper investigates the impact of spanwise orientated crossflow on the coherent unsteadiness within film cooling flows. Both cylindrical and shaped cooling holes, located on a blade pressure surface, are studied. The range of blowing ratios considered is 0.7-1.8 and the crossflow velocity is up to 0.8 times the bulk jet velocity. High Speed Photography and Hot Wire Anemometry are used to observe the presence of coherent unsteadiness, both immediately downstream of the hole exit and within the cooling hole tube.

Authors:

Richard J. Fawcett, Andrew P. S. Wheeler, Li He, Rupert Taylor

Publication:

International Journal of Heat and Fluid Flow

DOI:

10.1016/j.ijheatfluidflow.2013.01.001

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Stall Warning by Blade Pressure Signature Analysis

Authors:

Anna Young; Ivor Day; Graham Pullan

Publication:

J. Turbomach. 2012; 135(1):011033-011033-10.

DOI:

10.1115/1.4006426

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Overtip shock wave structure and its impact on turbine blade tip heat transfer

In this paper, the transonic flow pattern and its influence on heat transfer on a high-pressure turbine blade tip are investigated using experimental and computational methods. Spatially resolved heat transfer data are obtained at conditions representative of a single-stage high-pressure turbine blade (Mexit=1.0, Reexit=1.27×106, gap=1.5% chord) using the transient infrared thermography technique within the Oxford high speed linear cascade research facility. Computational fluid dynamics (CFD) predictions are conducted using the Rolls-Royce HYDRA/PADRAM suite. The CFD solver is able to capture most of the spatial heat flux variations and gives prediction results, which compare well with the experimental data. The results show that the majority of the blade tip experiences a supersonic flow with peak Mach number reaching 1.8. Unlike other low-speed data in the open literature, the turbine blade tip heat transfer is greatly influenced by the shock wave structure inside the tip gap. Obliqu

Authors:

Q. Zhang, D. O. O’Dowd, L. He, A. P. S. Wheeler, P. M. Ligrani and B. C. Y. Cheong

Publication:

Journal of Turbomachinery

DOI:

10.1115/1.4002949

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Turbine Blade Tip Heat Transfer in Low Speed and High Speed Flows

In this paper, high and low speed tip flows are investigated for a high-pressure turbine blade. Previous experimental data are used to validate a computational fluid dynamics (CFD) code, which is then used to study the tip heat transfer in high and low speed cascades. The results show that at engine representative Mach numbers, the tip flow is predominantly transonic. Thus, compared with the low speed tip flow, the heat transfer is affected by reductions in both the heat-transfer coefficient and the recovery temperature. The high Mach numbers in the tip region (M > 1.5) lead to large local variations in recovery temperature. Significant changes in the heat-transfer coefficient are also observed. These are due to changes in the structure of the tip flow at high speed. At high speeds, the pressure side corner separation bubble reattachment occurs through supersonic acceleration, which halves the length of the bubble when the tip-gap exit Mach number is increased from 0.1 to 1.0. In addit

Authors:

Andrew P. S. Wheeler, Nick R. Atkins, Li He

Publication:

Journal of Turbomachinery

DOI:

10.1115/1.4002424

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Experimental Investigation Into Unsteady Effects on Film Cooling

The benefits of different film cooling geometries are typically assessed in terms of their time-averaged performance. It is known that the mixing between the coolant film and the main turbine passage flow is an unsteady process. The current study investigates the forms of unsteadiness that occur in engine-representative film cooling flows and how this unsteadiness affects the mixing with the mainstream flow. Cylindrical and fan-shaped cooling holes across a range of hole blowing ratios have been studied experimentally using particle image velocimetry and high speed photography. Coherent unsteadiness is found in the shear layer between the jet and the mainstream for both cylindrical and fan-shaped cooling holes. Its occurrence and sense of rotation is found to be controlled by the velocity difference between the mainstream flow and the jet, which is largely determined by the blowing ratio.

Authors:

Richard J. Fawcett, Andrew P. S. Wheeler, Li He and Rupert Taylor

Publication:

Journal of Turbomachinery

DOI:

10.1115/1.4003053

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Estimating the Loss Associated With Film Cooling for a Turbine Stage

Authors:

Chia Hui Lim; Graham Pullan; John Northall

Publication:

J. Turbomach. 2011; 134(2):021011-021011-10.

DOI:

10.1115/1.4003255

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