A Modified Version of the RNG k–ε Turbulence Model for the Scale-Resolving Simulation of Internal Combustion Engines
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) engi...
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| Format: | Article |
| Language: | English |
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MDPI AG
2017-12-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/10/12/2116 |
| _version_ | 1811306070652485632 |
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| author | Vesselin Krassimirov Krastev Luca Silvestri Giacomo Falcucci |
| author_facet | Vesselin Krassimirov Krastev Luca Silvestri Giacomo Falcucci |
| author_sort | Vesselin Krassimirov Krastev |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-04-13T08:37:48Z |
| format | Article |
| id | doaj.art-67fb7532441e4efe895407312760163e |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-13T08:37:48Z |
| publishDate | 2017-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-67fb7532441e4efe895407312760163e2022-12-22T02:54:02ZengMDPI AGEnergies1996-10732017-12-011012211610.3390/en10122116en10122116A Modified Version of the RNG k–ε Turbulence Model for the Scale-Resolving Simulation of Internal Combustion EnginesVesselin Krassimirov Krastev0Luca Silvestri1Giacomo Falcucci2Department of Economics, Engineering, Society and Business Organization, University of Tuscia, 01100 Viterbo, ItalyDepartment of Enterprise Engineering “Mario Lucertini”, University of “Tor Vergata”, 00133 Rome, ItalyDepartment of Enterprise Engineering “Mario Lucertini”, University of “Tor Vergata”, 00133 Rome, ItalyThe 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.https://www.mdpi.com/1996-1073/10/12/2116internal combustion enginesturbulence modelingRNGscale-resolving simulationcycle-to-cycle variability |
| spellingShingle | Vesselin Krassimirov Krastev Luca Silvestri Giacomo Falcucci A Modified Version of the RNG k–ε Turbulence Model for the Scale-Resolving Simulation of Internal Combustion Engines Energies internal combustion engines turbulence modeling RNG scale-resolving simulation cycle-to-cycle variability |
| title | A Modified Version of the RNG k–ε Turbulence Model for the Scale-Resolving Simulation of Internal Combustion Engines |
| title_full | A Modified Version of the RNG k–ε Turbulence Model for the Scale-Resolving Simulation of Internal Combustion Engines |
| title_fullStr | A Modified Version of the RNG k–ε Turbulence Model for the Scale-Resolving Simulation of Internal Combustion Engines |
| title_full_unstemmed | A Modified Version of the RNG k–ε Turbulence Model for the Scale-Resolving Simulation of Internal Combustion Engines |
| title_short | A Modified Version of the RNG k–ε Turbulence Model for the Scale-Resolving Simulation of Internal Combustion Engines |
| title_sort | modified version of the rng k ε turbulence model for the scale resolving simulation of internal combustion engines |
| topic | internal combustion engines turbulence modeling RNG scale-resolving simulation cycle-to-cycle variability |
| url | https://www.mdpi.com/1996-1073/10/12/2116 |
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