Experimental study of recirculating flows induced by vane swirler

Abstract

The core objective of this study is to present the details of the experimental procedure and measurements made in an axisymmetric swirler model. The flow through 8 blade 30º vane swirler is studied experimentally. An overlap angle of 30º is provided between the vanes for the proper guidance of the flow through swirler. A hemi spherical bluff body is attached to the hub in order to overcome the inlet flow field distortion. A 5 mm diameter five-hole pitot sphere of cobra type has been used along with electronic digital manometers for the measurements. A computer aided traversing mechanism supported with Streamware software automatically controls the traversing of the probe. The recirculation velocities at the center core and corner regions are well captured with the five-hole probe. Five-hole pitot probe measurements along the entire length of the model at different stations, allow the determination of axial mean velocity component and pressure field parameters, which provide comprehensive information to aid and understand such complex recirculation flows. Flow field characteristics downstream of the swirler at different axial locations are examined in detail. The recirculation length and width are found to be strongly dependent on the amount of turbulence created by the vane swirler.