Confinement Effects on the Swirling Flow of a Counter-Rotating Swirl Cup

Abstract

Gas turbine combustor’s performance, emissions, operability, liner and dome temperature levels and gradients are affected by the degree of confinement expressed indirectly by the dome reference velocity. An experimental investigation was therefore undertaken to characterize the aerodynamic characteristics of non-reacting swirling flow generated by a counter-rotating swirl cup as affected by the test section dimensions. A two-component Laser Doppler Velocimetry (LDV) system was used to measure the mean velocity components and Reynolds stresses of the flowfield generated by the swirl cup installed in 8 square box test sections with width of 3.0, 4.0, 4.1, 4.3, 4.4, 4.5, 5.0, and 6.0 inch, in addition to unconfined flow. Measurements were carried out at fourteen axial distances ranging from 3 to 250 mm downstream of the flare exit, and the radial profiles are obtained through 2 mm intervals. Detailed experimental data are provided to improve mechanistic understanding of the swirl cup generated flowfield as impacted by the ratio of the test section cross-section to the mixer’s effective area. The benchmark quality data are planned for validating the state-of-the-art numerical models in addition more advanced LES approach.