Computational fluid dynamics modeling of combustion in heavy-duty diesel engines

Tabulated chemistry models allow to include detailed chemistry effects at low cost in numerical simulations of reactive flows. Characteristics of the reactive fluid flows are described by a reduced set of parameters that are representative of the flame structure at small scales so-called flamelets. For a specific turbulent combustion configuration, flamelet combustion closure, with proper formulation of the flame structure can be applied. In this study, flamelet generated manifolds (FGM) combustion closure with progress variable approach were incorporated with OpenFOAM ® source code to model combustion within compression ignition engines. For IC engine applications, multidimensional flamelet look-up tables for counter flow diffusive flame configuration were generated. Source terms of non-premixed combustion configuration in flamelet domain were tabulated based on pressure, temperature of unburned mixture, mixture fraction, and progress variable. A new frozen flamelet method was introduced to link one dimensional reaction diffusion space to multi-dimensional Computational Fluid Dynamics (CFD) physical space to fulfill correct modelling of thermal state of the engine at expansion stroke when charge composition was changed after combustion and reaction rates were subsided. Predictability of the developed numerical framework were evaluated for Sandia Spray A (constant volume vessel), Spray B (light duty optical Diesel engine), and a heavy duty Diesel engine experiments under Reynolds averaged Navier Stokes turbulence formulation. Results showed that application of multi-dimensional FGM combustion closure can comprehensively predict key parameters such as: ignition delay, in-cylinder pressure, apparent heat release rate, flame lift-off , and flame structure in Diesel engines.

show abstract

“…The virtual species approach was presented and validated by the authors. For more explanations of this approach reader can refer to [21,31,37].…”

Section: Numerical Implementationmentioning

confidence: 99%

Modelling compression ignition engines by incorporation of the flamelet generated manifolds combustion closure

Maghbouli

Akkurt

Lucchini

et al. 2018

Combustion Theory and Modelling

Self Cite

View full text Add to dashboard Cite

show abstract

“…Over the years it was successfully applied to simulation of spray and combustion in direct-injection engines [6,17,19] …”

Section: Computational Modelsmentioning

confidence: 99%

A comprehensive methodology for computational fluid dynamics combustion modeling of industrial diesel engines

Lucchini

Torre

Onorati

et al. 2017

International Journal of Engine Research

Self Cite

View full text Add to dashboard Cite

• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Link to publication• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Abstract. Combustion control and optimization is of great importance to meet future emission standards in Diesel engines: increase of bmep at high loads and extension of the operating range of advanced combustion modes seem to be the most promising solutions to reduce fuel consumption and pollutant emissions at the same time. Within this context, detailed CFD tools are required to predict the different involved phenomena such as fuel-air mixing, unsteady diffusion combustion and formation of noxious species. Detailed kinetics, consistent spray models and high quality grids are necessary to perform predictive simulations which can be used either for design or diagnostic purposes. In this work, the authors present a comprehensive approach which was developed using an open-source CFD code. To minimize the pre-processing time and preserve results accuracy, algorithms for automatic mesh generation of spray-oriented grids were developed and successfully applied to different combustion chamber geometries. The Lagrangian approach was used to describe the spray evolution while the combustion process is modeled employing detailed chemistry and, eventually, considering turbulence/chemistry interaction. The proposed CFD methodology was first assessed considering inert and reacting experiments in a constant volume vessel, where operating conditions typical of heavy duty Diesel Engines were reproduced. Afterwards, engine simulations were performed considering two different load points and two piston bowl geometries, respectively. Experimental validation was carried out by comparing computed and experimental data of in-cylinder pressure, heat release rate ...

show abstract

“…The proposed approach for combustion modeling based on tabulated kinetics was implemented in the Lib-ICE code which is based on the OpenFOAM R technology [24,25]. Experiments carried out in the context of the Engine Combustion Network (ECN) using n-dodecane as fuel at constant-volume conditions were used for a complete assessment of the proposed combustion models.…”

Section: Introductionmentioning

confidence: 99%

Modeling Non-Premixed Combustion Using Tabulated Kinetics and Different Fame Structure Assumptions

Lucchini¹,

D’Errico²,

Onorati³

et al. 2017

SAE Int. J. Engines

Self Cite

View full text Add to dashboard Cite

Nowadays, detailed kinetics is necessary for a proper estimation of both flame structure and pollutant formation in compression ignition engines. However, large mechanisms and the need to include turbulence/chemistry interaction introduce significant computational overheads. For this reason, tabulated kinetics is employed as a possible solution to reduce the CPU time even if table discretization is generally limited by memory occupation. In this work the authors applied tabulated homogeneous reactors (HR) in combination with different turbulent-chemistry interaction approaches to model non-premixed turbulent combustion. The proposed methodologies represent good compromises between accuracy, required memory and computational time. The experimental validation was carried out by considering both constant-volume vessel and Diesel engine experiments. First, the ECN Spray A configuration was simulated at different operating conditions and results from different flame structures are compared with experimental data of ignition delay, flame lift-off, heat release rates, radicals and soot distributions. Afterwards, engine simulations were carried out and computed data are validated by cylinder pressure and heat release rate profiles.

show abstract

Computational fluid dynamics modeling of combustion in heavy-duty diesel engines

Cited by 27 publications

References 25 publications

Modelling compression ignition engines by incorporation of the flamelet generated manifolds combustion closure

Modelling compression ignition engines by incorporation of the flamelet generated manifolds combustion closure

A comprehensive methodology for computational fluid dynamics combustion modeling of industrial diesel engines

Modeling Non-Premixed Combustion Using Tabulated Kinetics and Different Fame Structure Assumptions

Contact Info

Product

Resources

About