Study of LES Quality Criteria in a Motored Internal Combustion Engine

Ko, Insuk; D'Adamo, Alessandro; Fontanesi, Stefano; Min, Kyoungdoug

doi:10.4271/2017-01-0549

Cited by 18 publications

(11 citation statements)

References 28 publications

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“…Details on the boundary conditions and on the similarity between the experiments and the GT-Power results are illustrated in a previous work. 39 The use of cycle-independent boundary conditions is deemed to have a negligible impact on the ability to simulate cycle variability in the cylinder because of the presence of the two big plenums in the intake and exhaust line.…”

Section: Numerical Setupmentioning

confidence: 99%

Large eddy simulation analysis of the turbulent flow in an optically accessible internal combustion engine using the overset mesh technique

Rulli

Barbato

Fontanesi

et al. 2020

International Journal of Engine Research

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Computational fluid dynamics has become a fundamental tool for the design and development of internal combustion engines. The meshing strategy plays a central role in the computational efficiency, in the management of the moving components of the engine and in the accuracy of results. The overset mesh approach, usually referred to also as chimera grid or composite grid, was rarely applied to the simulation of internal combustion engines, mainly because of the difficulty in adapting the technique to the specific complexities of internal combustion engine flows. The article demonstrates the feasibility and the effectiveness of the overset mesh technique application to internal combustion engines, thanks to a purposely designed meshing approach. In particular, the technique is used to analyze the cycle-to-cycle variability of internal combustion engine flows using large eddy simulation. Fifty large eddy simulation cycles are performed on the well-known TCC-III engine in motored condition. Results are analyzed in terms of tumble center trajectory and using proper orthogonal decomposition to objectively characterize the spatial and temporal evolution of turbulent flow field in internal combustion engines. In particular, an original decomposition method previously applied by the authors to the TCC-III measured flow fields is here extended to computational fluid dynamics results.

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Section: Numerical Setupmentioning

confidence: 99%

Large eddy simulation analysis of the turbulent flow in an optically accessible internal combustion engine using the overset mesh technique

Rulli

Barbato

Fontanesi

et al. 2020

International Journal of Engine Research

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“…The bore × stroke values are equal to 92 × 86mm, with a (nominal) compression ratio of 10:1. This engine has already been the object of extensive numerical studies by the authors [26,27,35,36], in which the zonal hybrid methodology shown above has been implemented into the STAR-CD software [37] and then assessed and validated on a relatively fine computational grid (2×10 6 elements at the BDC). Nonetheless, a head-to-head comparison between the DES and DESx modes of operation was still missing and is, therefore, proposed here.…”

Section: Zonal-des Implementationmentioning

confidence: 99%

Standard and consistent Detached-Eddy Simulation for turbulent engine flow modeling: an application to the TCC-III engine

et al. 2020

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Multidimensional modeling of Cycle-to-Cycle Variability (CCV) has become a crucial support for the development and optimization of modern direct-injection turbocharged engines. In that sense, the only viable modeling options is represented by scale-resolving approaches such as Large Eddy Simulation (LES) or hybrid URANS/LES methods. Among other hybrid approaches, Detached-Eddy Simulation (DES) has the longest development story and is therefore commonly regarded as the most reliable choice for engineering-grade simulation. As such, in the last decade DESbased methods have found their way through the engine modeling community, showing a good potential in describing turbulence-related CCV in realistic engine configurations and at reasonable computational costs. In the present work we investigate the in-cylinder modeling capabilites of a standard two-equation DES formulation, compared to a more recent one which we call DESx. The DESx form differs from standard DES in the turbulent viscosity switch from URANS to LES-like behavior, which for DESx is fully consistent with Yoshizawa’s one-equation sub-grid scale model. The two formulations are part of a more general Zonal-DES (ZDES) methodology, developed and validated by the authors in a series of previous publications. Both variants are applied to the multi-cycle simulation of the TCC-III experimental engine setup, using sub-optimal grid refinement levels in order to stress the model limitations in URANS-like numerical resolution scenarios. Outcomes from this study show that, although both alternatives are able to ouperform URANS even in coarse grid arrangements, DESx emerges as sligthly superior and thus it can be recommended as the default option for in-cylinder flow simulation.

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“…In addition, it has already been the object of extensive LES studies at the University of Modena and Reggio Emilia ICE research group. 25,26…”

Section: Tcc-iii Engine Casementioning

confidence: 99%

“…A standard wall function approach is applied at the walls, 66,67 while pressure boundary conditions at the plenums are obtained from 1D simulations. 25,26,64 Implicit time integration is carried out through a compressible form of the Pressure-Implicit with Splitting of Operators (PISO) algorithm, with the time step length ranging from 0.1 to 0.05 CA around valve opening/closing timings.…”

Section: Tcc-iii Engine Casementioning

confidence: 99%

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Validation of a zonal hybrid URANS/LES turbulence modeling method for multi-cycle engine flow simulation

Krastev

D'Adamo

Berni

et al. 2019

International Journal of Engine Research

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A zonal hybridization of the RNG [Formula: see text]-[Formula: see text] URANS model is proposed for the simulation of turbulent flows in internal combustion engines. The hybrid formulation is able to act as URANS, DES or LES in different zones of the computational domain, which are explicitly set by the user. The resulting model has been implemented in a commercial computational fluid dynamics code and the LES branch of the modified RNG [Formula: see text]-[Formula: see text] closure has been initially calibrated on a standard homogeneous turbulence box case. Subsequently, the full zonal formulation has been tested on a fixed intake valve geometry, including comparisons with third-party experimental data. The core of the work is represented by a multi-cycle analysis of the TCC-III experimental engine configuration, which has been compared with the experiments and with prior full-LES computational studies. The applicability of the hybrid turbulence model to internal combustion engine flows is demonstrated, and PIV-like flow statistics quantitatively validate the model performance. This study shows a pioneering application of zonal hybrid models in engine-relevant simulation campaigns, emphasizing the relevance of hybrid models for turbulent engine flows.

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Study of LES Quality Criteria in a Motored Internal Combustion Engine

Cited by 18 publications

References 28 publications

Large eddy simulation analysis of the turbulent flow in an optically accessible internal combustion engine using the overset mesh technique

Large eddy simulation analysis of the turbulent flow in an optically accessible internal combustion engine using the overset mesh technique

Standard and consistent Detached-Eddy Simulation for turbulent engine flow modeling: an application to the TCC-III engine

Validation of a zonal hybrid URANS/LES turbulence modeling method for multi-cycle engine flow simulation

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