Publications

Showing 22 out of 82 publications matching your search

Modelling Turbine Acoustic Impedance

 We quantify the sensitivity of turbine acoustic impedance to aerodynamic design parameters. Impedance boundary conditions are an influential yet uncertain parameter in predicting the thermoacoustic stability of gas turbine combustors. We extend the semi-actuator disk model to cambered blades, using non-linear time-domain computations of turbine vane and stage cascades with acoustic forcing for validation data. Discretising cambered aerofoils into multiple disks improves reflection coefficient predictions, reducing error by up to an order of magnitude compared to a flat plate assumption. A parametric study of turbine stage designs using the analytical model shows acoustic impedance is a weak function of degree of reaction and polytropic efficiency. The design parameter with the strongest influence is flow coefficient, followed by axial velocity ratio and Mach number. We provide the combustion engineer with improved tools to predict impedance boundary conditions.

Authors:

J. Brind, G. Pullan

Publication:

International Journal of Turbomachinery, Propulsion and Power

DOI:

10.3390/ijtpp6020018

Download paper

Effect of Blade Row Interaction on Rotor Film Cooling

 The mechanisms of blade row interaction affecting rotor film cooling are identified to make recommendations for the design of film cooling in the real, unsteady turbine environment. Present design practice makes the simplifying assumption of steady boundary conditions despite intrinsic unsteadiness due to blade row interaction; we argue that if film cooling responds nonlinearly to unsteadiness, the time-averaged performance will then be in error. Nonlinear behavior is confirmed using experimental measurements of flat-plate cylindrical film cooling holes. Unsteady computations are used to identify the blade row interaction mechanisms in a high-pressure turbine rotor, and a quasi-steady model is used to predict unsteady excursions in momentum flux ratio. It is recommended that the designer should choose a cooling configuration that behaves linearly over the expected excursions in momentum flux ratio as predicted by a quasi-steady hole model.

Authors:

J. Brind, G. Pullan

Publication:

Journal of Turbomachinery

DOI:

10.1115/1.4047617

Download paper

Loss in Axial Compressor Bleed Systems

A new method for characterising bleed system loss is introduced, using research compressor test results as a demonstration case. A loss coefficient is defined for a control volume including only flow passing through the bleed system. The coefficient takes a measured value of 95% bleed system inlet dynamic head, and is shown to be a weak function of compressor operating point and bleed rate, varying by +/-2.2% over all tested conditions. This loss coefficient is the correct non-dimensional metric for quantifying and comparing bleed system performance.

Authors:

S.D. Grimshaw, J. Brind, G. Pullan, R. Seki

Publication:

Proceedings of ASME Turbo Expo 2019

A Web-Based Database Approach to CFD Post-Processing

Authors:

Graham Pullan

Publication:

AIAA 2017-0814

DOI:

10.2514/6.2017-0814

Download paper

Bleed Induced Distortion in Axial Compressors

Authors:

S. D. Grimshaw, G. Pullan, T. Walker

Publication:

Journal of Turbomachinery (2015) Vol. 137, Issue 9, Article 101009

DOI:

10.1115/1.4030809

Download paper

Modeling Nonuniform Bleed in Axial Compressors

Authors:

S.D. Grimshaw, G. Pullan, T.P. Hynes

Publication:

Journal of Turbomachinery (2016) Vol. 138, Issue 9, Article 091010

DOI:

10.1115/1.4032845

Download paper

Origins and Structure of Spike-Type Rotating Stall

Authors:

Pullan, G., Young, A.M., Day, I.J., Greitzer, E.M. and Spakovszky, Z.S.

Publication:

J. Turbomach 137(5), 051007 (May 01, 2015) (11 pages)

DOI:

10.1115/1.4028494

Download paper

Aerodynamic Design of High End Wall Angle Turbine Stages—Part I: Methodology Development

Authors:

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

Publication:

J. Turbomach. 2013; 136(2):021006-021006-8.

DOI:

10.1115/1.4023905

Download paper

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

Download paper

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

Download paper