Development and application of a computational fluid dynamics methodology to predict fuel–air mixing and sources of soot formation in gasoline direct injection engines

• 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

“…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%

“…Hence, mesh size and structure must be carefully chosen due to the well-known grid dependency problem. Following previous works, [17,18], separate models were applied to predict atomization and secondary breakup processes. This is expected to better reproduce the morphology and the evolution of sprays emerging from large nozzles.…”

Section: Spray Modelmentioning

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

show abstract

“…Fuel-air mixing simulations were carried out by using the Lib-ICE code, which is a set of libraries and solvers for IC engine modeling based on the OpenFOAM® technology. Over the years it was successfully applied to simulation of spray and combustion in direct-injection engines [31][32][33]. To describe atomization and secondary breakup, different combinations of sub-models were proposed over the years [34,35], all of them providing reasonably good results both at evaporating and nonPage 3 of 18 7/20/2015 evaporating conditions when applied to nozzles with diameters typical of passenger car engines.…”

Section: Numerical Setupmentioning

confidence: 99%

“…Following our previous work [32,34,35], separate models were applied to predict atomization and secondary breakup processes. This is expected to better reproduce the morphology and the evolution of sprays emerging from large nozzles.…”

mentioning

confidence: 99%

Experimental and Numerical Analyses of Liquid and Spray Penetration under Heavy-Duty Diesel Engine Conditions

Maes

Dam

Somers

et al. 2016

SAE Int. J. Fuels Lubr.

Self Cite

View full text Add to dashboard Cite

The modeling of fuel sprays under well-characterized conditions relevant for heavy-duty Diesel engine applications, allows for detailed analyses of individual phenomena aimed at improving emission formation and fuel consumption. However, the complexity of a reacting fuel spray under heavy-duty conditions currently prohibits direct simulation. Using a systematic approach, we extrapolate available spray models to the desired conditions without inclusion of chemical reactions. For validation, experimental techniques are utilized to characterize inert sprays of n-dodecane in a high-pressure, high-temperature (900 K) constant volume vessel with full optical access. The liquid fuel spray is studied using high-speed diffused back-illumination for conditions with different densities (22.8 and 40 kg/m 3 ) and injection pressures (150, 80 and 160 MPa), using a 0.205-mm orifice diameter nozzle. High-speed Schlieren imaging is used to analyze the influence of these boundary conditions on the spray penetration. Simulations of the fuel spray are performed using a dedicated computational mesh with refinements at the known location of the jet to capture the smallest scales of interest. Using a blob injection model refined with a primary atomization and secondary breakup model, correct trends and good agreement are achieved for both liquid and spray penetration. The capability of capturing the trends at largely varying boundary conditions with a single computational approach provides a solid base for future work.

show abstract

“…After every time-step, the progress variable C is evaluated and the equivalent reactor chemical composition is computed by means of the virtual species approach [14,12]. Progress variable is defined as in [13], with C being equal to the heat released by combustion, computed as the difference between the current and the initial value of the reactor formation enthalpy, also known as h 298 :…”

Section: Chemistry Table Generationmentioning

confidence: 99%

Experimental Validation of Combustion Models for Diesel Engines Based on Tabulated Kinetics in a Wide Range of Operating Conditions

Lucchini¹,

D’Errico²,

Cerri³

et al. 2017

SAE Technical Paper Series

Self Cite

View full text Add to dashboard Cite

Computational fluid dynamics represents a useful tool to support the design and development of Heavy Duty Engines, making possible to test the effects of injection strategies and combustion chamber design for a wide range of operating conditions. Predictive models are required to ensure accurate estimations of heat release and the main pollutant emissions within a limited amount of time. For this reason, both detailed chemistry and turbulence chemistry interaction need to be included. In this work, the authors intend to apply combustion models based on tabulated kinetics for the prediction of Diesel combustion in Heavy Duty Engines. Four different approaches were considered: wellmixed model, presumed PDF, representative interactive flamelets and flamelet progress variable. Tabulated kinetics was also used for the estimation of N O x emissions. The proposed numerical methodology was implemented into the Lib-ICE code, based on the OpenFOAM R technology, and validated against experimental data from a light-duty FPT engine. Ten points were considered at different loads and speeds where the engine operates under both conventional Diesel combustion and PCCI mode. A detailed comparison between computed and experimental data was performed in terms of in-cylinder pressure and NO x emissions.

show abstract

Development and application of a computational fluid dynamics methodology to predict fuel–air mixing and sources of soot formation in gasoline direct injection engines

Cited by 42 publications

References 24 publications

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

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

Experimental and Numerical Analyses of Liquid and Spray Penetration under Heavy-Duty Diesel Engine Conditions

Experimental Validation of Combustion Models for Diesel Engines Based on Tabulated Kinetics in a Wide Range of Operating Conditions

Contact Info

Product

Resources

About