Large-eddy simulation for the prediction of aerodynamics in IC engines

Thobois, L.; Rymer, G.; Soulères, T.; Poinsot, Thiérry; Heuvel, Bert van den

doi:10.1504/ijvd.2005.008468

Cited by 25 publications

(12 citation statements)

References 15 publications

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“…LES and RANS simulations of Diesel engine in-cylinder flow have been performed by Huijnen et al [17] who illustrated the importance of the numerical approach and of the inflow/outflow boundary conditions on the solution. Similar conclusions are drawn in the works of Thobois et al [32,33]. Multi-cycle LES simulations of non-reacting engine flow with realistic engine geometries have been performed by Thobois [31], Pischinger et al [24] and Goryntsev et al [11,12].…”

Section: Introductionsupporting

confidence: 80%

Large Eddy Simulation of Diesel Engine In-cylinder Flow

Bottone

Kronenburg

Gosman

et al. 2011

Flow Turbulence Combust

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The numerical simulation of the in-cylinder flow of a realistic Diesel engine is presented. Over the past three decades most of the CFD research for internal combustion engines (ICE) has been carried out using the Reynolds Averaged Navier Stokes (RANS) approach. Despite the achievements obtained in engine design, numerical investigations with RANS models can only give insight into the mean behaviour of the in-cylinder flow. By contrast, Large-Eddy Simulation (LES) allows a better description of the in-cylinder flow motion and gives access to the cycle-tocycle variations. Multi-cycle simulations of a motored case using LES and a hybrid LES/RANS approach are compared against experimental data and results obtained with a RANS methodology. The cycle-to-cycle variations in global in-cylinder characteristics such as pressure, swirl number and tumble number are reported and an analysis of the in-cylinder flow for each stroke of the engine cycle is presented. The interaction between spray and turbulence is also analysed with closed-chamber simulations. The effects of the hybrid RANS/LES approach on mixing of the vapour phase of the fuel is described and compared to the results obtained with a standard RANS approach. This work gives an insight into the numerical simulation of Diesel engine and illustrates some of the advantages of the LES methodology over RANS. The trade-off between computational cost and details in the flow description using a hybrid RANS/LES approach is discussed.

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Section: Introductionsupporting

confidence: 80%

Large Eddy Simulation of Diesel Engine In-cylinder Flow

Bottone

Kronenburg

Gosman

et al. 2011

Flow Turbulence Combust

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“…In spite of its relative simplicity, this case is quite popular among engine CFD modelers [7,[10][11][12][39][40][41], because of its close resemblance to an actual engine intake flow. Figure 2a sketches the domain configuration, while Table 2 contains the dimensional parameters and flow conditions used for the simulations' setup.…”

Section: Fixed Intake Valvementioning

confidence: 99%

“…For such a flow configuration, the in-cylinder axial pressure development can be divided into four stages [39,40]: a sudden pressure drop induced by the intake jet acceleration, with a minimum located around x/R c ≈ 0.25; a pressure peak at x/R c ≈ 0.75, as a result of the jet impingement on the wall; a second, weaker, pressure drop at x/R c ≈ 1, originated by the jet rebound; the final pressure recovery, which ends up at about x/R c ≈ 2.5. As for the isosurfaces in Figure 5, axial profiles are presented in Figure 6 in terms of the nondimensional pressure coefficient C p = 2(p − p out )/ρU 2 b , where p out is the reference pressure value at the cylinder outlet, ρ is the reference (constant) fluid density and U b is the inlet bulk velocity.…”

Section: Flow Structures and Axial Pressure Developmentmentioning

confidence: 99%

A Modified Version of the RNG k–ε Turbulence Model for the Scale-Resolving Simulation of Internal Combustion Engines

2017

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Abstract:The unsteady and random character of turbulent flow motion is a key aspect of the multidimensional modeling of internal combustion engines (ICEs). A typical example can be found in the prediction of the cycle-to-cycle variability (CCV) in modern, highly downsized gasoline direct injection (GDI) engines, which strongly depends on the accurate simulation of turbulent in-cylinder flow structures. The current standard for turbulence modeling in ICEs is still represented by the unsteady form of Reynold-averaged Navier Stokes equations (URANS), which allows the simulation of full engine cycles at relatively low computational costs. URANS-based methods, however, are only able to return a statistical description of turbulence, as the effects of all scales of motion are entirely modeled. Therefore, during the last decade, scale-resolving methods such as large eddy simulation (LES) or hybrid URANS/LES approaches are gaining increasing attention among the engine-modeling community. In the present paper, we propose a scale-resolving capable modification of the popular RNG k-ε URANS model. The modification is based on a detached-eddy simulation (DES) framework and allows one to explicitly set the behavior (URANS, DES or LES) of the model in different zones of the computational domain. The resulting zonal formulation has been tested on two reference test cases, comparing the numerical predictions with the available experimental data sets and with previous computational studies. Overall, the scale-resolved part of the computed flow has been found to be consistent with the expected flow physics, thus confirming the validity of the proposed simulation methodology.

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“…However, before applying LES to real engine cases, this technique was firstly applied on simplified engine configurations. Thobois et al [3,4] performed methodological studies about the LES applications to steady flow rings characterized by valves at fixed lift. The same steady state engine flow bench proposed in [3] was also carefully studied by the authors [5,6] adopting specific methodologies to evaluate the LES quality.…”

Section: Introductionmentioning

confidence: 99%

Boundary Conditions and SGS Models for LES of Wall-Bounded Separated Flows: An Application to Engine-Like Geometries

Piscaglia

Montorfano

Onorati

et al. 2013

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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and available online here Cet article fait partie du dossier thématique ci-dessous publié dans la revue OGST, Vol. 69, n°1, et téléchargeable ici D o s s i e rDOSSIER Edited by/Sous la direction de : C. Angelberger IFP Energies nouvelles International Conference / Les Rencontres Scientifiques d'IFP Energies nouvelles LES4ICE 2012 -Large Eddy Simulation for Internal Combustion Engine FlowsLES4ICE 2012 -La simulation aux grandes échelles pour les écoulements dans les moteurs à combustion interne Oil & Gas Science and Technology -Rev. IFP Energies nouvelles, Vol. 69 (2014) des e´coulements froids dans des ge´ome´tries complexes, comme dans les cylindres des moteurs a`combustion interne. L'imple´mentation de conditions aux limites a`l'entre´e pour la ge´ne´ration de turbulence synthe´tique et de deux mode`les des e´chelles infe´rieures a`la maille, le mode`le local dynamique de Smagorinsky et le mode`le SGS (Sub-Grid Scales) de viscosite´WALE (Wall-Adapting Local Eddy), est de´crite. Le mode`le WALE est baseś ur le carre´du tenseur du gradient de vitesse. Il prend en compte a`la fois les effets de la pression et du taux de rotation des plus petites fluctuations turbulentes de´tectables et il de´crit de manie`re ade´quate l'e´chelle y 3 a`proximite´des parois de la viscosite´turbulente sans ne´cessiter de pression dynamique. Il est ainsi cense´repre´senter un mode`le tre`s fiable pour les simulations ICE. La validation du mode`le a e´te´effectue´e sur deux bancs laminaires stationnaires : une ge´ome´trie a`gradin inverse´(backward-facing) et une ge´ome´trie simple de moteur a`combustion interne avec une unique vanne centrale. L'exhaustivite´de la simulation LES (i.e. la qualite´de la simulation LES) est aussi discute´e.Abstract -Boundary Conditions and SGS Models for LES of Wall-Bounded Separated Flows: An Application to Engine-Like Geometries -The implementation and the combination of advanced boundary conditions and subgrid scale models for Large Eddy Simulations are presented. The goal is to perform reliable cold flow LES simulations in complex geometries, such as in the cylinders of internal combustion engines. The implementation of an inlet boundary condition for synthetic turbulence generation and of two subgrid scale models, the local Dynamic Smagorinsky and the Wall-Adapting Local Eddy-viscosity SGS model (WALE) is described. The WALE model is based on the square of the velocity gradient tensor and it accounts for the effects of both the strain and the rotation rate of the smallest resolved turbulent fluctuations and it recovers the proper y 3 near-wall scaling for the eddy viscosity without requiring dynamic pressure; hence, it is supposed to be a very reliable model for ICE simulation. Model validation has been performed separately on two steady state flow benches: a backward facing step geometry and a simple IC engine geometry with one axed central valve. A discussion on the completeness of the LES simulation (i.e. LES simulation quality) is given.

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Large-eddy simulation for the prediction of aerodynamics in IC engines

Cited by 25 publications

References 15 publications

Large Eddy Simulation of Diesel Engine In-cylinder Flow

Large Eddy Simulation of Diesel Engine In-cylinder Flow

A Modified Version of the RNG k–ε Turbulence Model for the Scale-Resolving Simulation of Internal Combustion Engines

Boundary Conditions and SGS Models for LES of Wall-Bounded Separated Flows: An Application to Engine-Like Geometries

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