Some Developments in DES Modeling for Engine Flow Simulation

Krastev, Vesselin Krassimirov; Bella, Gino; Campitelli, Gennaro

doi:10.4271/2015-24-2414

Cited by 14 publications

(6 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The main reason for considering hybrid approaches for engine modeling is the increasingly compelling need for high-quality time and space resolved numerical data sets, but at a reduced computational cost compared to standard LES, as outlined in [8][9][10][11]. Most of the studies currently reported in the scientific literature are based on the Detached-Eddy Simulation (DES) concept and its derivatives [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27], while a few of them relies on the Scale-Adaptive Simulation (SAS) approach [15,16,28,29].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…Nonetheless, the development and application of URANS/LES hybrids for ICE simulation has marked a significant acceleration in recent years, 5 with a number of proposals including the scale-adaptive simulation (SAS) approach, 6–9 the dynamic length-scale resolution method (DLRM) 10,11 and both seamless and zonal formulations of the detached eddy simulation (DES) technique. 4,8,9,12–19 In order to be practically appealing, URANS/LES hybrids are expected to be at least as accurate as wall-modeled LES (WMLES), which is considered as the current standard for scale-resolving ICE simulations. 8,20–24 Furthermore, they are expected to bring additional benefits such as (a) easier management of boundary conditions at inlets/outlets (if open boundaries are placed in URANS-treated zones), (b) relaxed computational cost requirements (especially close to solid walls), (c) sharing of a common framework with URANS-based sub-models (wall treatment, combustion, etc.…”

Section: Introductionmentioning

confidence: 99%

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

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…Broadly speaking, a hybrid URANS/LES method should be based on the ability to adapt its behavior by applying the best-fitting modeling option with respect to the available numerical resolution. In the past 10 years, the number of engine-related hybrid modeling applications has been constantly increasing [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26], but hybrid/LP investigations are almost absent [27,28]. In our study, we evaluated two previously developed hybrid scale-resolving approaches [21,24,28,29] for a computational analysis of the "Spray G" reference GDI injector [30].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a Scale-Resolving Methodology for the Multidimensional Simulation of GDI Sprays

2019

View full text Add to dashboard Cite

The introduction of new emissions tests in real driving conditions (Real Driving Emissions—RDE) as well as of improved harmonized laboratory tests (World Harmonised Light Vehicle Test Procedure—WLTP) is going to dramatically cut down NOx and particulate matter emissions for new car models that are intended to be fully Euro 6d compliant from 2020 onwards. Due to the technical challenges related to exhaust gases’ aftertreatment in small-size diesel engines, the current powertrain development trend for light passenger cars is shifted towards the application of different degrees of electrification to highly optimized gasoline direct injection (GDI) engines. As such, the importance of reliable multidimensional computational tools for GDI engine optimization is rapidly increasing. In the present paper, we assess a hybrid scale-resolving turbulence modeling technique for GDI fuel spray simulation, based on the Engine Combustion Network “Spray G” standard test case. Aspects such as the comparison with Reynolds-averaged methods and the sensitivity to the spray model parameters are discussed, and strengths and uncertainties of the analyzed hybrid approach are pointed out. The outcomes of this study serve as a basis for the evaluation of scale-resolving turbulence modeling options for the development of next-generation directly injected thermal engines.

show abstract

Some Developments in DES Modeling for Engine Flow Simulation

Cited by 14 publications

References 30 publications

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

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

Evaluation of a Scale-Resolving Methodology for the Multidimensional Simulation of GDI Sprays

Contact Info

Product

Resources

About