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Detached eddy simulation of cyclic large scale fluctuations in a simplified engine setup

Hasse, C. and Sohm, V. and Durst, B. (2009):
Detached eddy simulation of cyclic large scale fluctuations in a simplified engine setup.
In: International Journal of Heat and Fluid Flow, pp. 32-43, 30, (1), DOI: 10.1016/j.ijheatfluidflow.2008.10.001, [Online-Edition: https://doi.org/10.1016/j.ijheatfluidflow.2008.10.001],
[Article]

Abstract

Computational Fluid Dynamics using RANS-based modelling approaches have become an important tool in the internal combustion engine development and optimization process. However, these models cannot resolve cycle to cycle variations, which are an important aspect in the design of new combustion systems. In this study the feasibility of using a Detached Eddy Simulation (DES) SST model, which is a hybrid RANS/LES model, to predict cycle to cycle variations is investigated. In the near wall region or in regions where the grid resolution is not sufficiently fine to resolve smaller structures, the two-equation RANS SST model is used. In the other regions with higher grid resolution an LES model is applied. The case considered is a geometrically simplified engine, for which detailed experimental data for the ensemble averaged and single cycle velocity field are available from Boree et al. Boree, J., Maurel, S., Bazile, R., 2002. Disruption of a compressed vortex, Physics of Fluids 14 (7), 2543-2556. The fluid flow shows a strong tumbling motion, which is a major characteristic for modern turbo-charged, direct-injection gasoline engines. The general flow structure is analyzed first and the extent of the LES region and the amount of resolved fluctuations are discussed. Multiple consecutive cycles are computed and turbulent statistics of DES SST, URANS and the measured velocity field are compared for different piston positions. Cycle to cycle variations of the velocity field are analyzed for both computation and experiment with a special emphasis on the useability of the DES SST model to predict cyclic variations. 2008 Elsevier Inc. All rights reserved.

Item Type: Article
Erschienen: 2009
Creators: Hasse, C. and Sohm, V. and Durst, B.
Title: Detached eddy simulation of cyclic large scale fluctuations in a simplified engine setup
Language: English
Abstract:

Computational Fluid Dynamics using RANS-based modelling approaches have become an important tool in the internal combustion engine development and optimization process. However, these models cannot resolve cycle to cycle variations, which are an important aspect in the design of new combustion systems. In this study the feasibility of using a Detached Eddy Simulation (DES) SST model, which is a hybrid RANS/LES model, to predict cycle to cycle variations is investigated. In the near wall region or in regions where the grid resolution is not sufficiently fine to resolve smaller structures, the two-equation RANS SST model is used. In the other regions with higher grid resolution an LES model is applied. The case considered is a geometrically simplified engine, for which detailed experimental data for the ensemble averaged and single cycle velocity field are available from Boree et al. Boree, J., Maurel, S., Bazile, R., 2002. Disruption of a compressed vortex, Physics of Fluids 14 (7), 2543-2556. The fluid flow shows a strong tumbling motion, which is a major characteristic for modern turbo-charged, direct-injection gasoline engines. The general flow structure is analyzed first and the extent of the LES region and the amount of resolved fluctuations are discussed. Multiple consecutive cycles are computed and turbulent statistics of DES SST, URANS and the measured velocity field are compared for different piston positions. Cycle to cycle variations of the velocity field are analyzed for both computation and experiment with a special emphasis on the useability of the DES SST model to predict cyclic variations. 2008 Elsevier Inc. All rights reserved.

Journal or Publication Title: International Journal of Heat and Fluid Flow
Volume: 30
Number: 1
Uncontrolled Keywords: Atmospheric temperature; Combustion; Computational fluid dynamics; Dynamics; Eddy currents; Engines; Equations of motion; Flow separation; Fluid dynamics; Internal combustion engines; Large eddy simulation; Model structures; Navier Stokes equations; Submarine geophysics; Thermochemistry; Transients; Turbulent flow; Vortex flow, Combustion systems; Compressed vortices; Consecutive cycles; Cycle to cycle variations; Cyclic variations; Eddy simulations; Experimental datums; Fluid flows; Grid resolutions; Hybrid RANS/LES; Injection gasoline engines; Internal combustions; LES models; Optimization processes; Set-ups; Single cycles; Special emphases; SST DES; Tumble; Tumbling motions; Turbulent statistics; Velocity fields; Wall regions, Mathematical models
Divisions: 16 Department of Mechanical Engineering > Simulation of reactive Thermo-Fluid Systems (STFS)
16 Department of Mechanical Engineering
Date Deposited: 29 Nov 2017 09:42
DOI: 10.1016/j.ijheatfluidflow.2008.10.001
Official URL: https://doi.org/10.1016/j.ijheatfluidflow.2008.10.001
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