Numerical Simulation of Pollutant Emissionand Flame Extinction in Lean Premixed Systems

Turbulent combustion;Pollutant emissions;CFD

Eggenspieler, Gilles ; Aerospace Engineering

University:Georgia Institute of Technology

Department:Aerospace Engineering

关键词: Turbulent combustion;    Pollutant emissions;    CFD;   

Others  :  https://smartech.gatech.edu/bitstream/1853/7161/1/eggenspieler_gilles_200508_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

Premixed and partially-premixed combustion and ollutant emissions in full-scale gas turbines hasbeen numerically investigated using a massively-parallel Large-Eddy Simulation Combustion Dynamics Model.Through the use of a flamelet library approach, it was observed that CO (Carbon Oxide) and NO (Nitric Oxide) emission can be predicted and match experimental results. The prediction of the CO emission trend is shown to be possible if the influence of the formation of UHC (Unburnt HydroCarbons) via flame extinction is taken into account. Simulations were repeated with twodifferent combustion approach: the G-equation model and the Linear-Eddy Mixing (LEM) Model. Results are similar for these two sets of numerical simulations.The LEM model was used to simulate flameextinction and flame lift-off in a dump combustion chamber. The LEM model is compared to the G-equation model and it was found that theLEM model is more versatile than the G-equation model with regard to accurate simulation of flame propagation in all turbulent premixed combustion regimes. With the addition of heat losses, flame extinction was observed for low equivalence ratio. Numerical simulation of flamepropagation with transient inflow conditions were also carriedout and demonstrated the ability of the LEM model toaccurately simulate flame propagation in the caseof a partially-premixed system.In all simulations where flame extinction andflame lift-off was simulated, release of unburnt fuelin the post-flame region through flame extinction was not observed.