A Sequential Chemical Kinetics-CFD-Chemical Kinetics Methodology to Predict HCCI Combustion and Main Emissions University of Antioquia

Format:

Conference/Event

Author/Creator:

Bedoya, Bedoya, author.

Contributor:

Aceves, Salvador

Cadavid, Francisco

Dibble, Robert

Flowers, Daniel

Saxena, Samveg

Conference Name:

SAE 2012 World Congress & Exhibition (2012-04-24 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2012

Summary:

This study presents the development of a new HCCI simulationmethodology. The proposed method is based on the sequentialcoupling of CFD analysis prior to autoignition, followed bymulti-zone chemical kinetics analysis of the combustion processduring the closed valve period. The methodology is divided intothree steps: 1) a 1-zone chemical kinetic model (Chemkin Pro) isused to determine either the intake conditions at IVC to achieve adesired ignition timing or the ignition timing corresponding withgiven IVC conditions, 2) the ignition timing and IVC conditions areused as input parameters in a CFD model (Fluent 6.3) to calculatethe charge temperature profile and mass distribution prior toautoignition, and 3) the temperature profile and mass distributionare fed into a multi-zone chemical kinetic model (Chemkin Pro) todetermine the main combustion characteristics.Different numbers of zones have been tested in the multi-zonestep to determine the effectiveness of the general methodology. 40zones are needed to achieve acceptable thermal stratificationresolution to accurately predict peak heat release rates, peakpressures rise rates and ringing intensity. However, a simplified12-zone reduced model is developed and validated to studycombustion variables. Simulation results for the main combustionvariables and emissions are compared with experimental results froma multi-cylinder HCCI engine fueled with biogas (60% CH₄ + 40%CO₂), and operating at different intake conditions. Comparisonsbetween the proposed numerical methodology and experimental resultsshow good agreement for power output (measured as IMEPg), indicatedefficiency, burn duration, peak pressure, individual ringingintensity, and HC and NOx emissions. CO emissions arevery sensitive to the input parameters of the 12-zone reducedmodel. However, when the peak temperature after ignition ofboundary layer zones is properly handled; CO emissions arereasonably well predicted. According to the results, themethodology can successfully predict combustion parameters andemissions for HCCI engines in which the fuel and air are well mixedprior to ignition. Compared with previous sequential methodologies,the method proposed here allows for reduced number of zones, moreuniform temperature profiles prior to ignition, more accurateestimation of mass located in each zone, reduced computing time andmore accurate predictions of peak heat release rates, peak pressurerise rates, and ringing intensity

Notes:

Vendor supplied data

Publisher Number:

2012-01-1119

Access Restriction:

Restricted for use by site license