Session: 04-22: Combustion Dynamics - Experiments I

Paper Number: 83234

83234 - Effect of Flare Geometry on the Flow Field of Radial-Radial Swirlers 

In this study, an experimental investigation has been conducted to assess the impact of the flare geometry on the mean flow field generated by radial-radial swirlers at a swirl number of 1.2. Two-dimensional two component particle image velocimetry (2D2C PIV) measurements have been performed on the mid-plane of the swirler exit in a non-reacting planar combustor test section at an air mass flow rate of 12.9 g/sec, corresponding to the Reynolds number of 35000 that is defined based on the hydraulic diameter and the mean swirler exit velocity. Double-frame images have been acquired at a recording rate of 20 Hz and total number of 2000 image pairs have been captured for each case to obtain a converged time-averaged flow field. In a previous study conducted in the same setup, co- & counter-rotating radial-radial swirlers without flare extension were investigated. The results revealed that the counter-rotating swirler has a V-shaped type flow field which is comprised of a central toroidal recirculation zone (CTRZ) and a corner recirculation zone (CRZ), whereas in the co-rotating configuration a dome-attached flow structure was observed without an existence of a CRZ. In this study, in addition to the previously tested two swirlers, six different swirlers have been tested with three different flare geometries (a filleted flare geometry and two chamfered flares at the angles of 26.5° and 45°) each having both co- and counter-rotating configurations. The results reveal the existence of a CTRZ for all swirler geometries with flare, but a CRZ is not observed in neither co- nor counter-rotating swirler configurations. This indicates that the introduction of the flare increases the degree of the radial expansion which forces the flow to follow the flare path and stick directly to the wall. The swirling jet then becomes a wall jet. In the case of the co-rotating configuration, regardless of the existence of the flare, the swirling flow immediately expands and attaches to the dome. The results of filleted flare and 45° chamfered flare geometries show similar characteristics in terms of the extent of the recirculation zone as well as the peak velocities at downstream locations, whereas the 26.5° chamfered flare introduces a relatively narrow recirculation zone with lower axial velocity magnitudes. Next, high-frequency pressure transducer measurements will be conducted to evaluate the effect of the flare geometry on the dynamics of the flow field.

Presenting Author: Ayse Bay Middle East Technical University

Presenting Author Biography: Performance Engineer in TUSAS Engine Industries since 2019. Works on experimental studies investigating swirling flow in Aerospace Engineering Department of the Middle East Technical University.

Authors:

Ayse Bay Middle East Technical University
Firat Kiyici Middle East Technical University
Mustafa Percin Middle East Technical University