TY - JOUR
T1 - Unsteady flow evolution in swirl injector with radial entry. I. Stationary conditions
AU - Wang, Shanwu
AU - Hsieh, Shih Yang
AU - Yang, Vigor
N1 - Funding Information:
This work was sponsored by the NASA Glenn Research Center under Grant No. NAG 3-2151. The support and encouragement from Kevin Breisacher is greatly appreciated. The authors are grateful for technical discussions with Dr. Jeff Cohen of United Technologies Research Center.
PY - 2005/4
Y1 - 2005/4
N2 - The vortical flow dynamics in a gas-turbine swirl injector were investigated by means of large eddy simulations. The flow enters the injector through three sets of radial-entry, counter-rotating swirl vanes. The formulation treats the Favre-filtered conservation equations in three dimensions along with a subgrid-scale model, and is solved numerically using a density-based, finite-volume approach with explicit time marching. Several methods, including proper orthogonal decomposition, spectral analysis, and flow visualization, are implemented to explore the flow dynamics in the complex three-dimensional flowfields. Various underlying mechanisms dictating the flow evolution, such as vortex breakdown, the Kelvin-Helmholtz instability, and helical instability, as well as their interactions, are studied for different swirl numbers. The flowfield exhibits well-organized motion in a low swirl-number case, in which the vortex shedding arising from shear instabilities downstream of the guide vanes drives acoustic oscillations of the mixed first tangential and first radial mode. The flowfield, however, becomes much more complicated at high swirl numbers, with each sub-regime dominated by different structures and frequency contents.
AB - The vortical flow dynamics in a gas-turbine swirl injector were investigated by means of large eddy simulations. The flow enters the injector through three sets of radial-entry, counter-rotating swirl vanes. The formulation treats the Favre-filtered conservation equations in three dimensions along with a subgrid-scale model, and is solved numerically using a density-based, finite-volume approach with explicit time marching. Several methods, including proper orthogonal decomposition, spectral analysis, and flow visualization, are implemented to explore the flow dynamics in the complex three-dimensional flowfields. Various underlying mechanisms dictating the flow evolution, such as vortex breakdown, the Kelvin-Helmholtz instability, and helical instability, as well as their interactions, are studied for different swirl numbers. The flowfield exhibits well-organized motion in a low swirl-number case, in which the vortex shedding arising from shear instabilities downstream of the guide vanes drives acoustic oscillations of the mixed first tangential and first radial mode. The flowfield, however, becomes much more complicated at high swirl numbers, with each sub-regime dominated by different structures and frequency contents.
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U2 - 10.1063/1.1874892
DO - 10.1063/1.1874892
M3 - Article
AN - SCOPUS:17444388029
VL - 17
SP - 045106-1-045106-13
JO - Physics of Fluids
JF - Physics of Fluids
SN - 1070-6631
IS - 4
M1 - 045106
ER -