Dr James Brind

Biography

Dr Brind is a Research Associate working with Mitsubishi Heavy Industries. He obtained his PhD at the Whittle Laboratory in 2019, for a thesis on the design of gas turbine cooling systems. Afterwards, he stayed at the Lab for postdoctoral work in aeroacoustics, developing analytical methods and computational fluid dynamics to predict how sound waves reflect from turbomachinery. He recieved the 2021 European Turbomachinery Conference Best Paper Award for a contribution in this area. His present work concerns centrifugal compressor design for heat pumps, an important technology for the decarbonisation of heating.

Publications & updates

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

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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

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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

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