Large-Eddy Simulation of a Jet in Cross flow Using Local Mesh Refinement

The reduction of full and part load emissions and the increase of the turndown ratio are important goals for gas turbine combustor development. Combustion techniques, which generate lower NOx emissions than unstaged premixed combustion in the full load range, and which have the potential of reducing minimum load while complying with emission legislation, are of high technical interest. Therefore, axial-staged combustion systems have been designed, either with or without expansion in a turbine stage between both stages. In its simpler form without intermediate expansion stage, a flow of hot combustion products is generated in the first stage of the premixed combustor, which interacts with the jets of premixed gas injected into the second stage. The level of NOx formation during combustion of the premixed jets in the hot cross flow determines the advantage of axially staged combustion regarding full load NOx emission reduction. Employing large-eddy simulation in openfoam, a tool has been developed, which allows to investigate staged combustion systems including not only temperature distribution but also NOx emissions under engine conditions. To be able to compute NOx formation correctly, the combustion process has to be captured with sufficient level of accuracy. This is achieved by the partially stirred reactor model. It is combined with a newly developed NOx model, which is a combination of a tabulation technique for the NOx source term based on mixture fraction and progress variable and a partial equilibrium approach. The NOx model is successfully validated with generic burner stabilized flame data and with measurements from a large-scale reacting jet in cross flow experiment. The new NOx model is finally used to compute a reacting jet in cross flow under engine conditions to investigate the NOx formation of staged combustion in detail. The comparison between the atmospheric and the pressurized configuration gives valuable insight in the NOx formation process. It can be shown that the NOx formation within a reacting jet in cross flow configuration is reduced and not only diluted.

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Large Eddy Simulation of Mixing in a Round Jet in Cross-Flow

39th AIAA Fluid Dynamics Conference ◽

10.2514/6.2009-3561 ◽

2009 ◽

Author(s):

Elmar Recker ◽

Walter Bosschaerts ◽

Patrick Hendrick

Keyword(s):

Large Eddy Simulation ◽

Cross Flow ◽

Round Jet ◽

Eddy Simulation ◽

Jet In Cross Flow ◽

Large Eddy

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Large-Eddy Simulation of Turbulent Mixing of a Jet in Cross-Flow

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4029915 ◽

2015 ◽

Vol 137 (9) ◽

Cited By ~ 3

Author(s):

Mostafa Esmaeili ◽

Asghar Afshari ◽

Farhad A. Jaberi

Keyword(s):

Large Eddy Simulation ◽

Velocity Profile ◽

Turbulent Mixing ◽

Mass Density ◽

Cross Flow ◽

Vortex Pair ◽

Complex Flow ◽

Eddy Simulation ◽

Jet In Cross Flow ◽

Large Eddy

An Eulerian–Lagrangian mathematical/computational methodology is employed for large-eddy simulation (LES) and detailed study of turbulent mixing in jet in cross-flow (JICF) configuration. Accurate prediction of mixing in JICF is crucially important to the development of advanced combustion systems. A high-order multiblock finite difference (FD) computational algorithm is used to solve the Eulerian velocity and pressure equations in a generalized coordinate system. The composition field, describing the mixing, is obtained from the filtered mass density function (FMDF) and its stochastic Lagrangian Monte-Carlo (MC) solver. Our simulations are shown to accurately predict the important flow features present in JICF such as the counter-rotating vortex pair (CVP), horseshoe, shear layer, and wake vortices. The consistency of the FD and MC parts of the hybrid LES/FMDF model is established for the simulated JICF in various conditions, indicating the numerical accuracy of the model. The effects of parameters influencing the jet penetration, entrainment, and turbulent mixing such as the jet velocity profile, and jet pulsation are investigated. The results show that the jet exit velocity profile significantly changes the trajectory and mixing of injected fluid. The jet pulsation is also shown to enhance the mixing depending on the flow Strouhal number. The LES/FMDF results are shown to be in good agreement with the available experimental data, confirming the reliability of LES/FMDF method for numerical simulation of turbulent mixing in complex flow configurations.

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Wall-Modelled Large-Eddy Simulation of a hot Jet-In-Cross-Flow with turbulent inflow generation

Computers & Fluids ◽

10.1016/j.compfluid.2014.06.015 ◽

2014 ◽

Vol 101 ◽

pp. 136-154 ◽

Cited By ~ 4

Author(s):

S. Bocquet ◽

J.-C. Jouhaud ◽

H. Deniau ◽

J.-F. Boussuge ◽

M.J. Estève

Keyword(s):

Large Eddy Simulation ◽

Cross Flow ◽

Eddy Simulation ◽

Turbulent Inflow ◽

Jet In Cross Flow ◽

Large Eddy

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Large Eddy Simulation of a Reacting Jet in Cross Flow With NOx Prediction

Volume 4A: Combustion, Fuels and Emissions ◽

10.1115/gt2016-56762 ◽

2016 ◽

Author(s):

Johannes Weinzierl ◽

Michael Kolb ◽

Denise Ahrens ◽

Christoph Hirsch ◽

Thomas Sattelmayer

Keyword(s):

Large Eddy Simulation ◽

Cross Flow ◽

Nox Emissions ◽

Staged Combustion ◽

Nox Formation ◽

Full Load ◽

Eddy Simulation ◽

Jet In Cross Flow ◽

Large Eddy ◽

Combustion Systems

The reduction of full and part load emissions and the increase of the turndown ratio are important goals for gas turbine combustor development. Combustion techniques, which generate lower NOx emissions than unstaged premixed combustion in the full load range, and which have the potential of reducing minimum load while complying with emission legislation, are of high technical interest. Therefore axial staged combustion systems have been designed, either with or without expansion in a turbine stage between both stages. In its simpler form without intermediate expansion stage a flow of hot combustion products is generated in the first stage of the premixed combustor, which interacts with the jets of premixed gas injected into the second stage. The level of NOx formation during combustion of the premixed jets in the hot cross flow determines the advantage of axially staged combustion regarding full load NOx emission reduction. Employing Large Eddy Simulation in OpenFOAM, a tool has been developed, which allows to investigate staged combustion systems including not only temperature distribution but also NOx emissions under engine conditions. To be able to compute NOx formation correctly the combustion process has to be captured with sufficient level of accuracy. This is achieved by the partially stirred reactor model. It is combined with a newly developed NOx model, which is a combination of a tabulation technique for the NOx source term based on mixture fraction and progress variable and a partial equilibrium approach. The NOx model is successfully validated with generic burner stabilized flame data and with measurements from a large scale reacting jet in cross flow experiment. The new NOx model is finally used to compute a reacting jet in cross flow under engine conditions to investigate the NOx formation of staged combustion in detail. The comparison between the atmospheric and the pressurized configuration gives valuable insight in the NOx formation process. It can be shown that the NOx formation within a reacting jet in cross flow configuration is reduced and not only diluted.

Download Full-text