Numerical modeling of combustion dynamics in a lean premixed combustor
The objective of this study was to evaluate the ability of a time-accurate, 2-D axi-symmetric CFD model to accurately predict combustion dynamics in a premixed pipe combustor driven by mixture feed variation. Independently measured data, including the magnitude and frequency of combustor pressure, were used to evaluate the model. The Smagorinsky, RGN k-{var{underscore}epsilon}, and molecular viscosity models were used to describe the subgrid turbulence, and a one-step, finite-rate reaction to equilibrium products model was used to describe the subgrid chemistry. Swirl source terms were included within the premix passage's computational domain and allowed the model to retain known boundary conditions at the choked flow inlet and the constant pressure exit. To ensure pressure waves were accurately captured, 1-D numerical analyses were first performed to assess the effects of boundary conditions, temporal and spatial differencing, time step, and grid size. It was found that the selected numerical details produced little numerical dissipation of the pressure waves. Then, 2-D axisymmetric analyses were performed in which the inlet temperature was varied. It was found that increases in the inlet temperature (keeping a constant mass flow rate) had a large effect on the unsteady combustor behavior since reaction and advection rates were increased. The correct trend of decreasing rms pressures with increasing inlet temperature was predicted. This agreement in rms pressure behavior supports the ability of the CFD model to accurately capture unsteady heat release and its coupling with resonant acoustic waves in multi-dimensional combustor systems. The effect of subgrid turbulence model was small for the unstable cases studied here.
- Research Organization:
- CFD Research Corp., Huntsville, AL (US)
- Sponsoring Organization:
- US Department of the Air Force
- OSTI ID:
- 20013531
- Resource Relation:
- Conference: 1998 International Joint Power Generation Conference, Baltimore, MD (US), 08/23/1998--08/26/1998; Other Information: PBD: 1998; Related Information: In: Proceedings of the 1998 international joint power generation conference (FACT-Vol.22). Volume 1: Fuels and combustion technologies; Gas turbines; Environmental engineering; Nuclear engineering, by Gupta, A.; Natole, R.; Sanyal, A.; Veilleux, J. [eds.], 921 pages.
- Country of Publication:
- United States
- Language:
- English
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