This content is not included in your SAE MOBILUS subscription, or you are not logged in.
A Multidimensional Interface for the Predictive CFD Simulation of the 2-Stroke Engine
ISSN: 0148-7191, e-ISSN: 2688-3627
Published November 13, 2006 by SAE International in United States
Annotation ability available
The two stroke engine has a wide range of application, especially in the field of recreational vehicles, handheld products and small two-wheelers. This is due to the advantages of the two stroke working principle: high power density, low weight, and low costs. In order to reduce the system-inherent disadvantages of the loop-scavenged two stroke engine developments using latest methods are necessary. One of these methods is the CFD simulation of the scavenging process, the high pressure cycle and the injection process. Reliable predictive simulation in the early development phase of a new engine is required to shorten the development time and to reduce prototype and test bench costs.
In previous investigations (1) [SAE 2005-32-0099; JSAE 20056552] the strategies for the simulation and the requirements for a predictive simulation were discussed. Finally a new methodology which bases on the combination of 3-dimensional (3D) and 0/1-dimensional (0/1D) CFD simulation was presented. For this methodology a new coupling interface is required.
In the current paper this newly developed interface and the implementation of the interface in a commercially available CFD-code is presented. The special feature of this coupling is the capability of being placed on any position in the 3D CFD mesh. Positioned in the opening port area between cylinder and exhaust port for instance, the coupling allows differing flow areas on both sides even with a non-conformal grid. The special treatment of the non-conformal respectively only partly overlapping flow cells also improves the convergence for the critical process of the exhaust port opening.
The multidimensional coupling interface is able to handle both 3D/3D and 3D/1D or 3D/0D connections. The 3D/1D and 3D/0D connections allow the replacement of regions with typically high numbers of cells by fast-calculating 0/1D models. Thus it is possible to replace the 3D mesh of the exhaust by a 1D exhaust model, respectively to connect the 3D code with 0D models for the crankcase and/or the reed-valve (2, 3). With this method a reduction of 3D cells and therefore computational time can be achieved. Therefore, the coupling interface is the basis for the creation of a tool box with “exchangeable parts”. This allows adjusting the model in the development process according to the required flow details, accuracy and available simulation time.
This paper includes the detailed discussion of the coupling interface and its validation based on test cases. Also the models which are necessary for the tool box are presented. The impact on the “every day” development work and an outlook on further steps conclude the paper.
- Rainer J. Rothbauer - Christian Doppler Laboratory “Thermodynamics of Reciprocating Engines”, Graz University of Technology
- Raimund A. Almbauer - Christian Doppler Laboratory “Thermodynamics of Reciprocating Engines”, Graz University of Technology
- Stephan P. Schmidt - Institute for Internal Combustion Engines and Thermodynamics, Graz University of Technology
- Roland H. Margelik - Institute for Internal Combustion Engines and Thermodynamics, Graz University of Technology
- Karl Glinsner - BRP Rotax
CitationRothbauer, R., Almbauer, R., Schmidt, S., Margelik, R. et al., "A Multidimensional Interface for the Predictive CFD Simulation of the 2-Stroke Engine," SAE Technical Paper 2006-32-0059, 2006, https://doi.org/10.4271/2006-32-0059.
- Rothbauer R. J., Margelik, R. Aslam, M. M. Almbauer, R. A. Schmidt, St. P. Glinsner K.: Predictive Simulation Strategies for the 2-Stroke Scavenging Process within the Scope of the Development Process”; 11th Small Engine Technology Conference (SETC 2005) SAE 2005-32-0099
- Zeng, Y. Strauss, S. Lucier, P. Craft T.: “Predicting and Optimizing Two-Stroke Engine Performance Using Multidimensional CFD”; SAE 2004-32-0039, 2004
- Blair G.P.: “Design and Simulation of Two-Stroke Engine”; Society of Automotive Engineers, Inc., 1996
- Willson B.: “Direct Injection as a Retrofit Strategy for Reducing Emissions from 2-Stroke Cycle Engines in Asia”; Hong Kong SAR, 2002
- Durst, Thams, Görg: “Frühzeitige Beurteilung des Einflusses komplexer Bauteile auf den Ladungswechsel mittels gekoppelter 1D-3D-Strömungsberechnung”, MTZ 61,2000
- Kirchberger R.: „Abgasoptimierung durch Einsatz von luftunterstützter Direkteinspritzung beim Zweitakt-Kleinmotor”, PhD-Theses, Graz University of Technology, 2003
- Chiavola O.: “A Multi-Dimensional CFD Transmission - Matrix Modelling of IC Engine Intake and Exhaust Systems”; Journal of Sound and Vibration (2002) 256(5), 835}848
- Chiatti, G. Chiavola O.: “Multicode Prediction of the Influence of the Exhaust System on the Performance of a Turbocharged Engine”, Journal of Engineering for Gas Turbines and Power, JULY 2002, Vol. 124 / 701
- Gerhart, Gross, Hochstein: „Fundamentals of Fluid Dynamics”, Addison-Wesley Publishing Company, 1985, ISBN 0-201-11410-0
- Pischinger, R. Klell M., Sams T.: „Die Thermodynamik der Verbrennungskraftmaschine“; 2.te Auflage, Helmut List „Der Fahrzeugantrieb”, Springer Verlag, Wien 2002, ISBN 3-211-83679-9
- Heywood J.: “Internal Combustion Engines Fundamentals”, McGraw-Hill, New York, 1988
- Toro: „Riemann Solvers and Numerical Methods for Fluid dynamics”, Springer, 1997, ISBN 3-540-61676-4
- Faires, Burden: “Numerische Methoden”, Spektrum Verlag, 1995, ISBN 3-86025-332-8,
- Thompson Kevin W.: „Time-Dependent Boundary Conditions for hyperbolic Systems”; Journal of Computational Physics 68, page 1-24, 1987
- Thompson Kevin W.: „Time-Dependent Boundary Conditions for hyperbolic Systems II”; Journal of Computational Physics 89, page 439-461, 1990
- Trescher, “Development of an Efficient 3-D CFD Software to Simulate and Visualize the Scavenging of a Two-Stroke Engine”, Dissertation, Freiburg 2005
- Cunningham G, Kee R J, Boyall J: “CFD prediction of crankcase flow regimes in a crankcase scavenged two stroke engine” SAE paper 970361, 1997
- van Leersum J.: “A numerical model of a high performance two-stroke engine”; Applied Numerical Mathematics 27 (1998) 83-108
- Blair, G. P., Hinds, E. T., Fleck, R. “Predicting the performance characteristics of two-cycle engines fitted with reed induction valves”, SAE paper 790842, 1979
- Cunningham, G Kee, R J Kenny R G: “Reed valve modelling in a computational fluid dynamics simulation of the two-stroke engine”, Proceedings Instn. Mech. Engineers Vol. 213 Part D, 1999
- Fleck, R., Blair, G. P., Houston, R. A. R. “An improved model for predicting reed valve behavior in two-stroke cycle engines”, SAE paper 871654, 1987.
- Mitianiec, Wladyslaw Bogusz Andrzej: “Theoretical and Experimental Study of Gas Flow Through Reed Valve in a Two-Stroke Engine”, SAE Paper 961802, 1996
- Onorati, A. Ferrari G. and D'Errico G.: “1D Unsteady Flows with Chemical Reactions in the Exhaust Duct-System of S.I. Engines: Predictions and Experiments”, SAE Paper 2001-01-0939, 2001
- Hirsch: „Numerical Computation of internal and external flows”, Wiley&Sons, 1990, ISBN 0-471-92351-6
- Andersen, Tannehill, Pletcher: „Computational Fluid Mechanics and Heat Transfer”, Hemispere Publishing Company, 1984, ISBN 0-07-050328-1