Measurements of tangential velocities and turbulent intensities were made at several radial positions in a cylinder under steady state flow conditions by LDV. Swirl was induced by an inclined intake nozzle in the cylinder. The LDV measurements were made in the dual beam forward scattering mode through a BK-7 window. For all measurements, 0.48μm PSL (polystyrene latex) particles were used for the seeding.
Selected intake flow rate were 1.37g/s, 2.28g/s and 3.2g/s, which were equivalent to the intake velocities at the engine speeds of 1500, 2500, 3500 rpm respectively. Swirl ratio could be computed by the velocity data measured at points equally spaced along x-and y-direction diameter and by linear interpolation on any particular section.
The center of swirl was not coincident with cylinder center but rather moved along the section. Tangential mean velocity and swirl ratio were increased in proportion to the angle of nozzle in cylinder.
