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Numerical simulation of a GDI engine flow using LES and POD

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conference contribution
posted on 09.05.2016, 11:26 by Nicholas J. Beavis, Salah IbrahimSalah Ibrahim, Weeratunge MalalasekeraWeeratunge Malalasekera
This paper presents the findings from a numerical study of a gasoline direct injection engine flow using the Large Eddy Simulation (LES) modelling technique. The study is carried out over 30 successive engine cycles. The study illustrates how the more simple but robust Smagorinsky LES sub-grid scale turbulence model can be applied to a complex engine geometry with realistic engineering mesh size and computational expense whilst still meeting the filter width requirements to resolve the majority of large scale turbulent structures. Detailed description is provided here for the computational setup, including the initialisation strategy. The mesh is evaluated using a turbulence resolution parameter and shows the solution to generally resolve upwards of 80% of the turbulence kinetic energy. The calculated mean and fluctuating velocity components have been validated across multiple cutting planes at key crank angles within the intake stroke with good agreement obtained against experimental data and compared with RANS model predictions. A Proper Orthogonal Decomposition (POD) technique is then used to evaluate the in-cylinder flow field with the results focusing around the eigenvalue/energy content and time coefficients associated with each mode. The findings have shown how this technique can be used to assess the amount of small scale turbulence generated at the point of spark timing, the level of flow field cyclic variability and the degree of statistical convergence to be expected from an ensemble average result based on the number of cycles and the level of cyclic variability present in the flow field.

Funding

This work was supported by Jaguar Land Rover and the UK-EPSRC grant EP/K014102/1 as part of the jointly funded Programme for Simulation Innovation.

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Aeronautical and Automotive Engineering

Published in

SAE Technical Papers

Citation

BEAVIS, N.J., IBRAHIM, S.S. and MALALASEKERA, W., 2016. Numerical simulation of a GDI engine flow using LES and POD. Presented at the SAE 2016 World Congress and Exhibition, 12th-14th April 2016, Detroit, Michigan.

Publisher

© SAE International

Version

NA (Not Applicable or Unknown)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Acceptance date

14/12/2015

Publication date

2016

Notes

This paper was published in SAE Technical Paper 2016-01-0598 and the definitive published version is available at http://dx.doi.org/10.4271/2016-01-0598

ISSN

0148-7191

Book series

SAE Technical Papers;2016-01-0598

Language

en

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Keywords

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