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Motored and Steady Flow Boundary Conditions Applied to the Prediction of Scavenging Flow in a Loop Scavenged Two-Stroke Cycle Engine
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Abstract
The application of in-cylinder multi-dimensional modelling to the scavenging process within the cylinder of a two-stroke cycle engine requires a prior knowledge of the flow entering that cylinder. Without this information, assumptions must be made which limit the accuracy of the theoretical simulation.
This paper describes laser doppler anemometry measurements of transfer port efflux flow for a two-port loop scavenged test cylinder motored at 200 rev/min. The cylinder was externally blown to ensure scavenge flow into the cylinder over the entire transfer port open period. The test results indicate that the flow does not enter the cylinder in the port design direction, but varies as a function of port height during both port opening and closing.
Comparison of motoring results with those obtained under steady flow testing of the same cylinder, shows adequate correlation, thereby justifying the use of steady flow information for dynamic simulation.
Incorporation of the measured LDA results as boundary conditions to the multi-dimensional modelling of isothermal scavenging produces very good correlation with experimental data. The predictions, obtained with the use of experimentally measured boundary conditions, are compared with those obtained using a assumption that flow enters the cylinder in the port design direction. Contour plots of the predicted in-cylinder fresh charge concentration are presented, which highlight the sensitivity of the scavenge process to the application of differing boundary conditions at cylinder entry.
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Citation
Smyth, J., Kenny, R., and Blair, G., "Motored and Steady Flow Boundary Conditions Applied to the Prediction of Scavenging Flow in a Loop Scavenged Two-Stroke Cycle Engine," SAE Technical Paper 900800, 1990, https://doi.org/10.4271/900800.Also In
References
- Sher E. “Modelling the Scavenging Process in the Two-Stroke Engine - An Overview” SAE International Congress Detroit, Michigan February 1989 SAE Paper No. 890414
- Sher E. “Prediction of the Gas Exchange Performance in a Two-Stroke Cycle Engine” SAE International Congress Detroit, Michigan February 1985 SAE Paper No. 850086
- Sweeney M. E. G. Swann G. B. G. Kenny R. G. Blair G. P. “Computational Fluid Dynamics Applied to Two-Stroke Engine Scavenging” SAE International Off-Highway and Powerplant Congress Milwaukee, Wisconsin September 1985 SAE Paper No. 851519
- Sweeney M. E. G. Kenny R. G. Swann G. B. G. Blair G. P. “Single Cycle Gas Testing Method for Two-Stroke Engine Scavenging” SAE International Congress Detroit, Michigan February 1985 SAE Paper No. 850178
- Ahmadi-Befrui B. Brandstatter W. Kratochwill H. “Multi-dimensional Calculation of the Flow Processes in a Loop-Scavenged Two-Stroke Cycle Engine” SAE International Congress Detroit, Michigan February 1989 SAE Paper No. 890841
- Smyth J. G. Kenny R. G. Blair G. P. “Steady Flow Analysis of the Scavenging Process in a Loop Scavenged Two-Stroke Cycle Engine - A Theoretical and Experimental Study” SAE International Off-Highway and Powerplant Congress Milwaukee, Wisconsin September 1988 SAE Paper No. 881267
- Kenny R. G. Smyth J. G. Fleck R. Blair G. P. “The Scavenging Process in the Two-Stroke Engine Cylinder” Motorcycle Symposium Graz University of Technology Graz April 1989
- Arcoumanis C. Whitelaw J. H. “Are Steady Flow Inlet Boundary Conditions Valid for Engine Cylinder Calculations”? Modelado en Motores de Combustion Interna 207 215 Valencia June 1987
- Bardsley M. E. A. Cajdeczko B. Boulouchos K. Cherhroudi B. Bracco F. V. “Measurements of the Three Components of Velocity in the Intake Ports of an I. C. Engine” SAE Internatioanl Congress Detroit, Michigan February 1989 SAE Paper No. 890792