Three-Dimensional Laser-Doppler Velocimeter Measurements in Swirling Turbulent Pipe Flow

摘要

The present work is an experimental study of the evolution characteristics of swirl in the flow in a pipe at a moderately high Reynolds number and over a wide range of swirl numbers characterising the swirl strength. The measurements are done by 3D LDV in a specially designed facility that works on the principle of refractive-index matching. Swirl with the well-defined distribution of a constant angular velocity is introduced into the test section of this facility by a swirl generating device in which a tube bundle in the pipe rotates about the pipe axis. The measurements have been processed to yield the mean-velocity vector and the Reynolds stress tensor in this flow. An analysis of the measured evolution characteristics brings out a dominant effect of swirl with a solid body rotation as the annihilation of Reynolds shear streses.