Session: 04-19 Combustor Design I
Paper Number: 125726
125726 - Matching Turbulence to a Target Profile in a Flexible Combustor Simulator Design
We address the generation of tuneable turbulence in a combustor simulator representative of engine conditions. To support a wide range of future engine designs with different properties, including lean burn and novel fuels for low-emissions scenarios, we seek the production, prediction and control of turbulence meeting a variable 2-d target specification at the high-pressure (HP) turbine nozzle guide vane (NGV), to be achieved simultaneously with other variable target properties including the temperature and velocity profile of the flow.
We discuss appropriate parameters with which to define the turbulence target, including measures of turbulence intensity and length scales. We describe the quantification of the turbulent dynamics as a transport problem for turbulent correlation functions from upstream generation to downstream target plane.
Using a simplified duct model with a programmatically defined mesh, within a production computational fluid dynamics (CFD) solver, we simulate various means of turbulence generation, including combinations of small-scale grids and large-scale obstacles. We find that obstacles collectively possessing geometrical features in both directions perpendicular to the stream are useful, because they can generate wakes in one direction that are large but are then broken up in the other direction, resulting in an intense turbulence field with an intermediate degree of homogeneity.
In these simulations, a k–ω model was employed to parameterize sub-grid turbulence scales, but the overall turbulent kinetic energy density in most of the domain was dominated not by this k but by the unsteady fluctuations at resolved grid and larger scales.
In future work we intend to verify these results by performing large eddy simulations (LES) to resolve smaller scales, using a more detailed and more realistic geometry.
Presenting Author: Greg Colyer University of Oxford
Presenting Author Biography: Greg Colyer is a researcher at the Department of Engineering Science, and a lecturer in physics at Trinity College, University of Oxford. He was previously a researcher in planetary atmospheric dynamics, at Oxford and at Exeter. His doctoral thesis, in Theoretical Physics at Oxford, concerned turbulent energy transport in the MAST plasma experiment at Culham. He has also worked in the commercial sector, and on the JPEG international standards committee.
Authors:
Greg Colyer University of OxfordHaidong Li Rolls-Royce plc
Saturnin Richard Adoua Rolls-Royce plc
Paul Beard University of Oxford
Luca Di Mare University of Oxford
Matching Turbulence to a Target Profile in a Flexible Combustor Simulator Design
Paper Type
Technical Paper Publication