Large-eddy simulation and acoustic analysis of a turbulent flow field in a swirl-stabilized combustor

Abstract

To conduct a comprehensive study on the flow characteristics and acoustic oscillation in a gas turbine combustor, a 3D large-eddy simulation (LES) was implemented. The formulation consists of the Favre-filtered conservation equations of mass, momentum, and energy. The subgrid-scale dynamics are modeled using a compressible flow version of the Smagorinsky model. To investigate the dominant coherent structure, the proper orthogonal decomposition (POD) method was used for post-processing. The combustor of concern is the LM6000, lean-premixed dry low-NOx annular combustor, developed by General Electric Aircraft Engines (GEAE). Four important characteristics of swirl flow are visualized: vortex breakdown, procession and dissipation of vortical structures, recirculation zones, and helical waves immediately downstream of the swirl injector. It is shown that the turbulent motion of swirl flow directly affects acoustic oscillation through the cycle and spectral analysis. The four most dominant acoustic modes are extracted from the flow field by the POD analysis. The transverse modes in the y and z directions are dominant in all four modes, since the pressure fields are significantly affected by swirl flow.

Mixing Characteristics of Kerosene-Lox in a Swirl Injector at 100 bar

“…The coefficient, CI, can be calculated in a leastsquare method to minimize the error: preconditioning scheme [11]. The code is paralleled using an MPI library for more effective calculation [12][13][14].…”

Effect of Dynamic SGS Model in a Kerosene-LOx Swirl Injector under Supercritical Condition

“…The real-gas fluid thermodynamic relation is applied to a preconditioning scheme [20]. The code is paralleled using an MPI library for a more effective calculation [21][22][23]. Figure 1 shows the coaxial swirl injector geometry as well as the swirl numbers of liquid oxygen, and kerosene, at 1.598 and 6.548, respectively [24].…”

“…11 shows the timeaveraged mixing efficiency. In both models, the efficiency increases as it moves downstream after the (21) where Y Fuel is the mass fraction of kerosene. The parameter α is determined by relating the local equivalence ratio, ϕ local to the global equivalence ratio, ϕ glocal .…”

Investigation of Isothermal Flow inside a New Combustor with Two-Stage Axial Swirler

“…LES methods are very effective for studying various turbulence characteristics of swirl stabilized combustor. They can be effectively used for treatment and studying dissipation of vortex breakdown and swirl structure, as well as angular recirculating zone and central recirculating zone, important characteristics of swirl (Kim et al 2011, Tiwari et al 2020. Canepa et al (2006) has shown that the complex flow field structure comes from vortex breakdown.…”