Investigation of Swirling Flows in Ducts

摘要

The work reports on theoretical and experimental investigations of swirling flows in cylindrical ducts. Steady state solutions were obtained for laminar incompressible swirling flow in the entrance region of a straight circular duct of uniform cross section by solving the complete Navier Stokes equations using the stream function, the angular momentum and the tangential component of vorticity as variables. The analysis was also adapted to the solution of unsteady flows and as an example, an impulsively started flow was treated. In addition, a method was suggested for the study of the hydrodynamic stability of laminar swirling flows. Finally it was demonstrated that for the flows under consideration the analytical incompressible solutions are also representative of the characteristics of swirling compressible flows. In the experimental part of the investigation, a swirling flow of air was observed in a thirty-inch long, three-inch diameter duct. (Author)