Quantification of volumetric in-cylinder flow of SI engine usign 3D laser doppler velocimetry 2000-05-0035
The flow inside of an internal combustion engine is highly
complex and varies greatly among different engine types. For a long
time IC engine researchers have tried to classify the major mean
flow patterns and turbulence characteristics using different
measurement techniques. During the last three decades tumble and
swirl numbers have gained increasing popularity in mean flow
quantification while turbulent kinetic energy has been used for the
measurement of turbulence in the cylinder.
In this paper, simultaneous 3-D LDV measurements of the
in-cylinder flows of the three different engines are summarized for
the quantification of the flow characteristics. The ensemble
averaged velocity, tumble and swirl motions, and turbulence kinetic
energy during the intake and compression strokes were examined from
the measured velocity data (approximately 2,000 points for each
case) by the 3-D LDV system. In-cylinder flow patterns were studied
using ensemble-averaged velocity vectors in each vertical or
horizontal plane, and in entire volume. The result showed that the
flow is affected not only by the intake system but by the aspect
ratio of the cylinder. Tumble and swirl ratios, and turbulence
kinetic energy were quantified as planar and volumetric quantities.
The measurements and calculation results were animated for the
visualization of the flow, and hence ease to analysis. The
animation can also be used for the comparison and validation of the
flow predicted by CFD codes.
Keunchul C. Lee, Seoung-Chool Yoo, Harold J. Schock
University of Alabama, Halla Institute of Technology, Michigan State Univ.