Limitations of Sector Mesh Geometry and Initial Conditions to Model Flow and Mixture Formation in Direct-Injection Diesel Engines
Published April 2, 2019 by SAE International in United States
Downloadable datasets for this paper availableAnnotation of this paper is available
Sector mesh modeling is the dominant computational approach for combustion system design optimization. The aim of this work is to quantify the errors descending from the sector mesh approach through three geometric modeling approaches to an optical diesel engine. A full engine geometry mesh is created, including valves and intake and exhaust ports and runners, and a full-cycle flow simulation is performed until fired TDC. Next, an axisymmetric sector cylinder mesh is initialized with homogeneous bulk in-cylinder initial conditions initialized from the full-cycle simulation. Finally, a 360-degree azimuthal mesh of the cylinder is initialized with flow and thermodynamics fields at IVC mapped from the full engine geometry using a conservative interpolation approach. A study of the in-cylinder flow features until TDC showed that the geometric features on the cylinder head (valve tilt and protrusion into the combustion chamber, valve recesses) have a large impact on flow complexity. As a result, errors in near-TDC swirl ratio, vortex structure and turbulence availability were seen when employing sector meshing, even if a 360-degree sector, with direct IVC flow mapping, was used. During injection, lack of geometric details on the head led to the inability to predict the formation of an upper recirculation region on the tumbling plane, above the piston step, which has been associated with thermal efficiency benefits with the stepped-lip bowl. Initialization of the flow anisotropies in the cylinder resulting from the intake process at IVC were instead seen to have a smaller effect. The results also showed that tuning IVC quantities in a sector mesh cannot effectively compensate for its missing geometric and flow details.
CitationPerini, F., Busch, S., Kurtz, E., Warey, A. et al., "Limitations of Sector Mesh Geometry and Initial Conditions to Model Flow and Mixture Formation in Direct-Injection Diesel Engines," SAE Technical Paper 2019-01-0204, 2019, https://doi.org/10.4271/2019-01-0204.
Data Sets - Support Documents
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- Dimitriou, P., Wang, W., and Peng, Z., “A Piston Geometry and Nozzle Spray Angle Investivation in a DI Diesel Engine by Quantifying the Air-Fuel Mixture,” International Journal of Spray and Combustion Dynamics 7(1):1-24, 2014.
- Vassallo, A., “Combustion System Design and Development Process for Modern Automotive Diesel Engines,” in SAE 13th International Conference on Engines & Vehicle (ICE2015), Naples, Italy, 2015.
- Schramm, C., Gruenig, C., Brauer, M. and Diezemann, M., “Piston Bowl Optimization for a Diesel Engine with Variable Compression Ratio,” in STAR Global Conference 2016, Prague, 2016.
- Manuel, A., Gonzalez, D., Borman, G., and Reitz, R., “A Study of Diesel Cold Starting using both Cycle Analysis and Multidimensional Calculations,” SAE Technical Paper 910180, 1991, doi:10.4271/910180.
- Amsden, A.A., O’Rourke, P.J., and Butler, T.D., “KIVA-II: A Computer Program for Chemically Reactive Flows with Sprays,” Los Alamos National Laboratories LA-11560-MS, Los Alamos, NM, 1989.
- Reitz, R.D. and Rutland, C.J., “Development and Testing of Diesel Engine CFD Models,” Progress in Energy and Combustion Science 21(2):173-196, 1995.
- Ge, H.-W., Shi, Y., Reitz, R.D., Wickman, D.D. et al., “Heavy-Duty Diesel Combustion Optimization Using Multi-Objective Genetic Algorithm and Multi-Dimensional Modeling,” SAE Technical Paper 2009-01-0716, 2009, doi:10.4271/2009-01-0716.
- Shrivastava, R., Hessel, R.P., and Reitz, R.D., “CFD Optimization of DI Diesel Engine Performance and Emissions Using Variable Intake Valve Actuation with Boost Pressure, EGR and Multiple Injections,” SAE Technical Paper 2002-01-0959, 2002, doi:10.4271/2002-01-0959.
- Wickman, D.D., Senecal, P.K., and Reitz, R.D., “Diesel Engine Combustion Chamber Geometry Optimization Using Genetic Algorithms and Multi-Dimensional Spray and Combustion Modeling,” SAE Technical Paper 2001-01-0547, 2001, doi:10.4271/2001-01-0547.
- Bergman, M., Fredriksson, J., and Golovitchev, V.I., “CFD-Based Optimization of a Diesel-fueled Free Piston Engine Prototype for Conventional and HCCI Combustion,” SAE Int. J. Engines 1(1):1118-1143, 2009, doi:10.4271/2008-01-2423.
- Kurtz, E. and Styron, J., “An Assessment of Two Piston Bowl Concepts in a Medium-Duty Diesel Engine,” SAE Int. J. Engines 5(2):344-352, 2012, doi:10.4271/2012-01-0423.
- Miles, P.C. and Andersson, O., “A Review of Design Considerations for Light-Duty Diesel Combustion Systems,” International Journal of Engine Research 17(1):6-15, 2016.
- Perini, F. and Reitz, R.D., “FRESCO - An Object-Oriented, Parallel Platform for Internal Combustion Engine Simulations,” in 28th International Multidimensional Engine Modeling User’s Group Meeting at the SAE Congress, Detroit, 2018.
- Wang, B.-L., Miles, P.C., Reitz, R.D., and Han, Z., “Assessment of RNG Turbulence Modeling and the Development of a Generalized RNG Closure Model,” SAE Technical Paper 2011-01-0829, 2011, doi:10.4271/2011-01-0829.
- Perini, F., Busch, S., Zha, K., and Reitz, R.D., “Comparison of Linear, Non-linear and Generalized RNG-Based k-Epsilon Models for Turbulent Diesel Engine Flows,” SAE Technical Paper 2017-01-0561, 2017, doi:10.4271/2017-01-0561.
- Perini, F. and Reitz, R.D., “Improved Atomization, Collision and Sub-Grid Scale Momentum Coupling Models for Transient Vaporizing Engine Sprays,” International Journal of Multiphase Flows 79:107-123, 2016.
- Reitz, R.D. and Bracco, F.V., “On the Dependence of Spray Angle and Other Spray Parameters on Nozzle Design and Operating Conditions,” SAE Technical Paper 790494, 1979, doi:10.4271/790494.
- Beale, J.C. and Reitz, R.D., “Modeling Spray Atomization with the Kelvin-Helmholtz/Reyleigh-Taylor Hybrid Model,” Atomization and Sprays 19(7):623-650, 1999.
- Munnannur, A. and Reitz, R.D., “Comprehensive Collision Model for Multidimensional Engine Spray Computations,” Atomization and Sprays 9(6):597-619, 2009.
- Torres, D.J., O’Rourke, P.J., and Trujillo, M.F., “A Discrete Multicomponent Fuel Model,” Atomization and Sprays 13(2&3):42, 2003.
- Perini, F., Dempsey, A.B., Reitz, R.D., Sahoo, D. et al., “A Computational Investigation of the Effects of Swirl Ratio and Injection Pressure on Mixture Preparation and Wall Heat Transfer in a Light-Duty Diesel Engine,” SAE Technical Paper 2013-01-1105, 2013, doi:10.4271/2013-01-1105.
- “ECN Data Search Page,” https://ecn.sandia.gov/ecn-data-search/, accessed Aug. 28, 2018.
- Busch, S., “Light-Duty Diesel Combustion,” in DOE Vehicle Technologies Office and Hydrogen and Fuel Cells Program Annual Merit Review, Washington, DC, 2017.
- Busch, S., Zha, K., Kurtz, E., Warey, A. et al., “Experimental and Numerical Studies of Bowl Geometry Impacts on Thermal Efficiency in a Light-Duty Diesel Engine,” SAE Technical Paper 2018-01-0228, 2018, doi:10.4271/2018-01-0228.
- Busch, S., Zha, K., Perini, F., Reitz, R.D. et al., “Bowl Geometry Effects on Turbulent Flow Structure in a Direct Injection Diesel Engine,” SAE Technical Paper 2018-01-1794, 2018, doi:10.4271/2018-01-1794.
- Busch, S. and Miles, P.C., “Parametric Study of Injection Rates with Solenoid Injectors in an Injection Quantity and Rate Measuring Device,” in ASME Paper No. ICEF2014-5583, Columbus, IN, 2015.
- Sandia Mational Laboratories, “Small-Bore Diesel Engine,” Aug. 11, 2017, https://ecn.sandia.gov/engines/engine-facilities/small-bore-diesel-engine/, accessed 2018.
- Perini, F., Reitz, R.D., and Miles, P.C., “A Comprehensive Modeling Study of In-Cylinder Fluid Flows in a High-Swirl, Light-Duty Optical Diesel Engine,” Computers and Fluids 105:113-124, 2014.
- Perini, F., Zha, K., Busch, S., Kurtz, E. et al., “Piston Geometry Effects in a Light-Duty, Swirl-Supported Diesel Engine: Flow Structure Characterization,” International Journal of Engine Research, vol. OnlineFirst, 2017.
- Zha, K., Busch, S., Warey, A., Peterson, R.C. et al., “A Study of Piston Geometry Effects on Late-Stage Combustion in a Light-Duty Optical Diesel Engine Using Combustion Image Velocimetry,” SAE Technical Paper 2018-01-0230, 2018, doi:10.4271/2018-01-0230.
- Dempsey, A.B., Wang, B.-L., Reitz, R.D., Petersen, B. et al., “Comparison of Quantitative In-Cylinder Equivalence Ratio Measurements with CFD Predictions for a Light Duty Low Temperature Combustion Diesel Engine,” SAE Int. J. Engines 5(2):162-184, 2012, doi:10.4271/2012-01-0143.
- Petersen, B.R. and Miles, P.C., “PIV Measurements in the Swirl-Plane of a Motored Light-Duty Diesel Engine,” SAE Int. J. Engines 4(1):1623-1641, 2011, doi:10.4271/2011-01-1285.
- Perini, F., Zha, K., Busch, S., Miles, P.C. et al., “Principal Component Analysis and Study of Port-Induced Swirl Structures in a Light-Duty Optical Diesel Engine,” SAE Technical Paper 2015-01-1696, 2015, doi:10.4271/2015-01-1696.
- Zha, K., Busch, S., Miles, P.C., Wijeyakulasuriya, S. et al., “Characterization of Flow Asymmetry During the Compression Stroke Using Swirl-Plane PIV in a Light-Duty Optical Diesel Engine with the Re-entrant Piston Bowl Geometry,” SAE Int. J. Engines 8(4):1837-1855, 2015, doi:10.4271/2015-01-1699.
- Perini, F., Sahoo, D., Miles, P.C., and Reitz, R.D., “Modeling the Ignitability of a Pilot Injection for a Diesel Primary Reference Fuel: Impact of Injection Pressure, Ambient Temperature and Injected Mass,” SAE Int. J. Fuels Lubr. 7:48-64, 2014, doi:10.4271/2014-01-1258.
- Han, Z. and Reitz, R.D., “A Temperature Wall Function Formulation for Variable-Density Turbulent Flows with Application to Engine Convective Heat Transfer Modeling,” International Journal of Heat and Mass Transfer 40(3):613-625, 1997.
- Perini, F., Hiraoka, K., Nomura, K., Yuuki, A. et al., “An Efficient Level-Set Flame Propagation Model for Hybrid Unstructured Grids using the G-Equation,” SAE Int. J. Engines 9(3):1409-1424, 2016.