The potential of statistical RANS to predict knock tendency: Comparison with LES and experiments on a spark-ignition engine

D'Adamo, Alessandro; Breda, Sebastiano; Berni, Fabio; Fontanesi, Stefano

doi:10.1016/j.apenergy.2019.04.093

Cited by 34 publications

(19 citation statements)

References 63 publications

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“…MI k (11) with N being the total number of sampling points over the FOV. Expressions (11) can be enhanced with the addition of Kinetic Energy (KE)-based weights in the averaging operator [26]:…”

Section: Resultsmentioning

confidence: 99%

“…Less common, but with a rapidly evolving track record in the past ten years, is the implementation of hybrid URANS/LES models for the scale-resolving simulation of flow through internal combustion engines [7]. 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%

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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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Section: Resultsmentioning

confidence: 99%

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

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“…Even in a RANS framework, ensemble averaged turbulence may affect the local thermal and mixing state, which in turn can induce variations in the reactivity of the unburnt charge. To account for mixture reactivity dispersion around the average, a statistical knock model was proposed by d'Adamo et al [10,27,28]. The model, hereafter called GK-PDF, is based on the reconstruction of the physical states whose presence is statistically accounted for in the same fluid cell.…”

Section: Statistical Knock Modelmentioning

confidence: 99%

Comparison Between Experimental and Simulated Knock Statistics Using an Advanced Fuel Surrogate Model

et al. 2020

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The statistical tendency of a GDI spark-ignition engine to undergo knocking combustion as a consequence of spark timing variation is numerically investigated. In particular, attention is focused on the importance to match combustion-relevant and knock-relevant fuel properties to ensure consistency with the experimental evidence. An inhouse surrogate formulation methodology is used to emulate real gasoline properties, comparing fuel models of increasing complexity. Knock is investigated using a proprietary statistical knock model (GruMo Knock Model, GK-PDF). The model can infer a log-normal distribution of knock intensity within a RANS formalism, by means of transport equations for variances and turbulence-derived probability density functions (PDFs) for physical quantities. The calculated distributions are compared to measured statistical distributions. The proposed numerical/experimental comparison constitutes an advancement in synthetic chemistry integration into 3D-CFD combustion simulations.

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“…The proposed threshold has been tested in a mock-up setup using model-based tools (ETAS INTECRIO) and Simulink, and a similar approach has been applied to pressure sensor signals by [18]. Probabilistic modeling of knock occurrence has also been applied by [19]. The authors used different input parameters related to the engine such as mixture fraction, enthalpy and temperature of unburned gases.…”

Section: Introductionmentioning

confidence: 99%

Real-Time Knock Characterization Using Adaptive Filters and Power Estimators

et al. 2020

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We combined adaptive filters associated with power estimators to characterize the knock signal, obtained from a knock sensor, in an internal combustion engine. The filters were implemented using the automotive model-based design methodology, and the resulting software was embedded into hardware for a real-time evaluation of the proposed solution. The knock signals could be qualitatively identified in real-time, and thus have the potential to aid in the management of flexible-fuel engines. This approach has an extensive range of applications within the automotive industry, since it can be implemented within any model-based control strategy. For example, this methodology can be applied in commercial ECUs, currently used in most vehicles for knock detection, by simply eliminating an internal, dedicated, integrated circuit for knock identification, or by serving as a redundancy device (i.e: for safety purposes). Finally, this methodology can identify the knock signal, obtained from a knock sensor, just by using an algorithm implemented in the ECU's processor, which we show is identifiable in real-time.

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The potential of statistical RANS to predict knock tendency: Comparison with LES and experiments on a spark-ignition engine

Cited by 34 publications

References 63 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

Comparison Between Experimental and Simulated Knock Statistics Using an Advanced Fuel Surrogate Model

Real-Time Knock Characterization Using Adaptive Filters and Power Estimators

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