This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Near-Wall Velocity Characteristics in Valved and Ported Motored Engines
Annotation ability available
Sector:
Language:
English
Abstract
To study the near-wall velocity characteristics, gas velocity measurements have been made near the cylinder head of a motored four-stroke engine using Laser Doppler Velocimetry (LDV), and near-wall flow characteristics have been observed in three different two-stroke geometries using Particle Image Velocimetry (PIV) and particle photographs.
The results of these studies show that the behavior of the fluid near the wall depends on the engine intake geometry, combustion chamber geometry, and operating condition. The near-wall velocity characteristics tend to be one of two forms. In one form, the behavior is one of an extended region of low momentum fluid, where an imbalance in radial pressure gradient forces and centripetal forces exists because of the combined effects of fluid rotation and shear. Such a flow can be seen in engines with gas exchange systems that do not promote scrubbing of the wall, and in cylinder geometry that does not cause flow normal to the wall. However, the most common form found in engines is characterized by a very-thin layer of low momentum fluid, with direct interaction of the wall and turbulent structures. This form is typical of engines with overhead valves or two-stroke engines with boost ports. Conventional boundary layers apparently do not exist in engines because of fluid rotation, wall scrubbing, and the short time available for formation.
Recommended Content
Citation
Pierce, P., Ghandhi, J., and Martin, J., "Near-Wall Velocity Characteristics in Valved and Ported Motored Engines," SAE Technical Paper 920152, 1992, https://doi.org/10.4271/920152.Also In
References
- Foster, D.E. Witze, P.O. “Velocity Measurements in the Wall Boundary Layer of a Spark Ignited Research Engine,” SAE Paper 872105 1987
- Hall, M.J. Bracco, F.V. “Cycle-Resolved Velocity and Turbulence Measurements Near the Cylinder Wall of a Firing S.I. Engine,” SAE Paper 861530 1986
- Reuss, D.L. Adrian, R.J Landreth, C.C. French, D.T. Fansler, T.D. “Instantaneous Planar Velocity and Large-Scale Vorticity and Strain Rate in an Engine Using Particle-Image Velocimetry,” SAE Paper No. 890616 1989
- Yang, J. “Convective Heat Transfer Predictions and Experiments in an IC Engine,” University of Wisconsin-Madison 1988
- Yang, J. Pierce, P. Martin, J.K. Foster, D.E. “Heat Transfer Predictions and Experiments in a Motored Engine,” SAE Paper 881314 1988
- Durst, F. Melling, A. Whitelaw, J.H. Principles and Practice of Laser Doppler Anemometry 2nd Academic Press 1981
- Kreid, D.K. “Laser-Doppler Velocimeter Measurements in Nonuniform Flow: Error Estimates,” Applied Optics 13 8 1974
- Hong, N.S. Jones, A.R. Weinberg, F.J. “Doppler Velocimetry Within Turbulent Phase Boundaries,” Proc. R. Soc., A, 353 1977
- Trump, D.D. Goss, L.P. Chen, T.H. “Combined CARS-LDV System for Turbulent Flame Studies,” Central States Section of the Comb. Inst. May 1988
- Witze, P.O. Martin, J.K. “Cyclic-Variation Biases in Spark Ignition Engine Turbulence Measurements,” Second Int'l Sym. on App. of Laser Anemometry of Fluid Mechanics July 1984
- Pierce, P.H. Near Wall Velocity Measurements in a Motored Four-Stroke Engine University of Wisconsin-Madison 1991
- Reuss, D.L. Bardsley, M. Felton, P.G. Adrian, R.J. Landreth, C.C. “Velocity, Vorticity, and Strain-Rate Ahead of a Flame Measured in an Engine Using Particle Image Velocimetry,” SAE Paper 900053 1990
- Adrian, R.J. Yao, C.S. “Development of Pulsed Laser Velocimetry for Measurement of Fluid Flow,” Applied Optics 24 1 1985
- Ghandhi, J.B. “Velocity Field Characteristics in Motored Two-Stroke Ported Engines,” University of Wisconsin-Madison 1991
- Boggs, D.L. Borman, G.L. “Spatially-Resolved Measurements of Instantaneous Engine Heat Flux,” SAE Paper 910721 1991
- Schlichting, H. Boundary Layer Theory McGraw-Hill New York 1955
- Greenspan, H.P. The Theory of Rotating Fluids Cambridge University Press 1969