Large Eddy Simulation of a Gas-Turbine Combustor Using 2-Scalar Flamelet Approach

2007 ◽  
Author(s):  
Takuji Nakashima ◽  
Nobuyuki Oshima
Keyword(s):  
Large Eddy Simulation ◽  
Gas Turbine ◽  
Turbulent Combustion ◽  
Numerical Prediction ◽  
Premixed Combustion ◽  
Combustion Reaction ◽  
Combustion Model ◽  
Gas Turbine Combustor ◽  
Eddy Simulation ◽  
Large Eddy

To investigate the ability of a numerical prediction method in a practical combustor system, we have conducted a numerical simulation of partially premixed turbulent combustion within a gas-turbine combustor geometry. A combination of Large-Eddy simulation and the 2-scalar flamelet approach are used to simulate unsteady turbulent combustion in modeling turbulent and combustion reaction phenomena and their interactions. With the successful simulation of both the premixed and non-premixed combustion states including the effects of turbulence, the predicted distributions of time-averaged temperature and the O2 mole fraction are found to essentially correspond to the experimental data. In an analysis of the predicted results, the weights of resolved and unresolved phenomena in the numerical prediction are estimated in order to discuss the effects of the turbulent combustion model applied to a practical combustion flow. The analysis determines the effect of turbulence on a Grid Scale that accelerates the premixed combustion reaction, while the modeled effect of turbulence caused by combustion acceleration as shown on a Sub-grid Scale is about twice of the effect as that seen on the Grid Scale.

Large-Eddy Simulation With a New Flamelet Model for Partially Premixed Combustion in a Gas-Turbine Combustor

2017 ◽  
Author(s):  
Keisuke Tanaka ◽  
Tomonari Sato ◽  
Nobuyuki Oshima ◽  
Jiun Kim ◽  
Yusuke Takahashi ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Diffusion Flame ◽  
Premixed Combustion ◽  
Combustion Model ◽  
Gas Turbine Combustor ◽  
Flamelet Model ◽  
Eddy Simulation ◽  
Partially Premixed Combustion ◽  
Large Eddy ◽  
Partially Premixed

Turbulent combustion flows in the partially premixed combustion field of a dry low-emission gas-turbine combustor were investigated numerically by large-eddy simulation with a 2-scalar flamelet model. Partially premixed combustion was modelled with 2-scalar coupling based on the conservative function of the mixture fraction and the level set function of the premixed flame surface; the governing equations were then used to calculate the gas temperature in the combustion field with flamelet data. A new combustion model was introduced by defining a nondimensional equilibrium temperature to permit the calculation of adiabatic flame temperatures in the combustion field. Furthermore, a conventional G-equation was modified to include spatial gradient terms for the adiabatic flame temperature to facilitate smooth propagation of a burnt-state region in a predominantly diffusion flame. The effect of flame curvature was adjusted by means of an arbitrary parameter in the equation. The simulation results were compared with those from an experiment and a conventional model. Qualitative comparisons of the instantaneous flame properties showed a dramatic improvement in the new combustion model. Moreover, the experimental outlet temperature agreed well with that predicted by the new model. The model can therefore reproduce the propagation of a predominantly diffusion flame in partially premixed combustion.

scholarly journals Large Eddy Simulation of a Bluff Body Stabilized Lean Premixed Flame

2014 ◽  
Vol 2014 ◽  
pp. 1-18 ◽  
Author(s):  
A. Andreini ◽  
C. Bianchini ◽  
A. Innocenti
Keyword(s):  
Large Eddy Simulation ◽  
Gas Turbine ◽  
Turbulent Combustion ◽  
Bluff Body ◽  
Sensitivity Study ◽  
Flame Stabilization ◽  
Combustion Model ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Lean Premixed

The present study is devoted to verify current capabilities of Large Eddy Simulation (LES) methodology in the modeling of lean premixed flames in the typical turbulent combustion regime of Dry LowNOxgas turbine combustors. A relatively simple reactive test case, presenting all main aspects of turbulent combustion interaction and flame stabilization of gas turbine lean premixed combustors, was chosen as an affordable test to evaluate the feasibility of the technique also in more complex test cases. A comparison between LES and RANS modeling approach is performed in order to discuss modeling requirements, possible gains, and computational overloads associated with the former. Such comparison comprehends a sensitivity study to mesh refinement and combustion model characteristic constants, computational costs, and robustness of the approach. In order to expand the overview on different methods simulations were performed with both commercial and open-source codes switching from quasi-2D to fully 3D computations.

Large Eddy Simulation of Turbulent Combustion Flows in Gas Turbine Combustor

2002 ◽  
Author(s):  
Takuji Tominaga ◽  
Nobuyuki Taniguchi ◽  
Yuichi Itoh ◽  
Toshio Kobayashi
Keyword(s):  
Large Eddy Simulation ◽  
Gas Turbine ◽  
Turbulent Combustion ◽  
Equivalence Ratio ◽  
Equation Model ◽  
Gas Turbine Combustor ◽  
Turbine Engine ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Annular Combustor

In this paper, Large Eddy Simulation (LES) and G-equation model based on flamelet concept are demonstrated in axially staged annular combustor of gas turbine engine. G-equation model is extended for combustion in a non-uniform equivalence ratio of premixed gas. Using this model, the simulations of the flame propagation are executed with different spatial distribution of the equivalence ratios. In order to compare the results, experiments for combustion and non-combustion flows in the modeled combustor are also performed. The flow field can be predicted by LES and be agreed with the experimental results essentially. The flame propagating behaviors depending on the equivalence ratios are represented by the extended G-equation model.

Large-Eddy Simulation of Reacting Turbulent Flows in Complex Geometries

2005 ◽  
Vol 73 (3) ◽  
pp. 374-381 ◽  
Author(s):  
K. Mahesh ◽  
G. Constantinescu ◽  
S. Apte ◽  
G. Iaccarino ◽  
F. Ham ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Gas Turbine ◽  
Turbulent Flows ◽  
Reacting Flows ◽  
Gas Turbine Combustor ◽  
Turbine Engine ◽  
Progress Variable ◽  
Eddy Simulation ◽  
Variable Approach ◽  
Large Eddy

Large-eddy simulation (LES) has traditionally been restricted to fairly simple geometries. This paper discusses LES of reacting flows in geometries as complex as commercial gas turbine engine combustors. The incompressible algorithm developed by Mahesh et al. (J. Comput. Phys., 2004, 197, 215–240) is extended to the zero Mach number equations with heat release. Chemical reactions are modeled using the flamelet/progress variable approach of Pierce and Moin (J. Fluid Mech., 2004, 504, 73–97). The simulations are validated against experiment for methane-air combustion in a coaxial geometry, and jet-A surrogate/air combustion in a gas-turbine combustor geometry.

Large-Eddy Simulation of a Gas Turbine Combustor Flow

1999 ◽  
Vol 143 (1-6) ◽  
pp. 25-62 ◽  
Author(s):  
WON-WOOK KIM ◽  
SURESH MENON ◽  
HUKAM C. MONGIA
Keyword(s):  
Large Eddy Simulation ◽  
Gas Turbine ◽  
Gas Turbine Combustor ◽  
Eddy Simulation ◽  
Large Eddy
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