Predicting Emissions Using CFD Simulations of an E30 Gasoline Surrogate in an HCCI Engine with Detailed Chemical Kinetics Reaction Design

Format:

Conference/Event

Author/Creator:

Puduppakkam, Puduppakkam, author.

Contributor:

Bunting, Bruce

Liang, Long

Meeks, Ellen

Naik, Chitralkumar V.

Shelburn, Anthony

Conference Name:

SAE 2010 World Congress & Exhibition (2010-04-13 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2010

Summary:

To accurately predict emissions as well as combustion phasing ina homogeneous charge compression ignition (HCCI) engine, detailedchemistry needs to be used in Computational Fluid Dynamics (CFD)modeling. In this work, CFD simulations of an Oak Ridge NationalLaboratory (ORNL) gasoline HCCI engine have been performed withfull coupling to detailed chemistry. Engine experiments using anE30 gasoline surrogate blend were performed at ORNL, which includedmeasurements of several trace species in the exhaust gas. CFDmodeling using a detailed mechanism for the same fuel compositionused in the experiments was also performed. Comparisons betweendata and model are made over a range of intake temperatures. The(experiment and model) surrogate blend consists of 33 wt %ethanol, 8.7 % n-heptane and 58.3 % iso-octane. The data andsimulations involve timing sweeps using intake temperature tocontrol combustion phasing at a constant fuel rate. The modelinguses a detailed chemical kinetic mechanism consisting of 428species and 2378 reactions. This mechanism was obtained by atargeted mechanism reduction of a well validated master kineticsmechanism for multiple gasoline surrogate-fuel components, whichconsists of 3553 species and 14904 reactions. A 15-degree sectormesh consisting of 53,800 cells at IVC has been used for the closedvalve simulations.The CFD simulation employs the newly developed FORTÉ simulationpackage, which was designed to take advantage of advanced chemistrysolver methodologies as well as advanced spray models. In thisstudy, there is no spray model used, since the fuel is atomized andquickly vaporized during port injection. However, parallelcomputing, dynamic adaptive chemistry and dynamic cell clusteringmethods have been used to minimize the chemistry relatedcomputational time while maintaining accuracy in the kineticspredictions. These methods allow inclusion of the relatively large(428 species) detailed kinetics mechanism directly in thesimulation, while keeping the overall simulation time reasonablefor production work.Comparisons with the engine data include the trends ofcombustion phasing as a function of intake temperatures. Emissionsof several species are also compared with engine data. The ORNLengine experiments included detailed exhaust measurements ofNOx, CO, formaldehyde, acetaldehyde, methane, ethylene,propene, iso-butylene and the overall unburned hydrocarbons. All ofthese exhaust measurements have been compared with the modelingresults, as a function of intake temperatures. The results agreewell with the engine data, and the agreement provides confidence inthe predictive capability of the model for studying chemistry andfuel effects

Notes:

Vendor supplied data

Publisher Number:

2010-01-0362

Access Restriction:

Restricted for use by site license