Chemical structure of autoignition in a turbulent lifted H2/N2 jet flame issuing into a vitiated coflow

In the present paper autoignition is studied as the main stabilization mechanism in turbulent lifted H2/N2 jet flames issuing into a vitiated hot coflow. The numerical study is performed using the joint scalar PDF approach with detailed chemistry in a two dimensional axisymmetric domain. The SSG Reynolds stress model is used as a turbulence model in the simulation. Chemical structure and characteristics of autoignition are investigated using various methods and parameters. Reaction rate analysis is made to analyze the ignition process at the flame base. The results show the occurrence of a chain branching reaction preceding thermal runaway, which boosts the chain branching process in the flame. This demonstrates the large impact of autoignition at the flame base on the stabilization of the lifted turbulent flame. Further investigation using the scatter-plots of scalars reveals the characteristics of the ignition. The relation between the behavior of temperature and of key intermediate species demonstrates the formation of OH through consumption of HO2 at nearly isothermal conditions in a very lean-fuel mixture at the flame base. Flux analyses in the conservation equations of species are used to explore the impacts of mass transport on ignition process. Ignition is found to be mainly controlled by chemical features rather than the mixing processes near the flame base. Characteristics of autoignition are also investigated in terms of Damkohler number and progress variable.

[1]  R. Barlow,et al.  Simultaneous Laser Raman-rayleigh-lif Measurements and Numerical Modeling Results of a Lifted Turbulent H2/N2 Jet Flame in a Vitiated Coflow , 2002 .

[2]  Thomas,et al.  [American Institute of Aeronautics and Astronautics 43rd AIAA Aerospace Sciences Meeting and Exhibit - Reno, Nevada ()] 43rd AIAA Aerospace Sciences Meeting and Exhibit - Numerical Simulation of Aerodynamic Plasma Actuator Effects , 2005 .

[3]  R. Yetter,et al.  Flow reactor studies and kinetic modeling of the H2/O2 reaction , 1999 .

[4]  K. Ahn,et al.  Level‐set based flamelet approach for simulating turbulent lifted jet flame , 2008 .

[5]  Konstantinos Gkagkas,et al.  The impact of reduced chemistry on auto-ignition of H2 in turbulent flows , 2009 .

[6]  俊治 榎本,et al.  43rd AIAA Aerospace Sciences Meeting and Exhibit , 2005 .

[7]  S. Chung.  Stabilization, propagation and instability of tribrachial triple flames , 2007 .

[8]  R. Miake-Lye,et al.  Lifted turbulent jet flames: A stability criterion based on the jet large-scale structure , 1989 .

[9]  L. Su,et al.  Experimental investigation of stabilization mechanisms in turbulent, lifted jet diffusion flames , 2006 .

[10]  L. Vanquickenborne,et al.  The stabilization mechanism of lifted diffusion flames , 1966 .

[11]  A. Masri,et al.  Simultaneous Rayleigh temperature, OH-and CH2O-LIF imaging of methane jets in a vitiated coflow , 2008 .

[12]  Bassam B. Dally,et al.  Structure of turbulent non-premixed jet flames in a diluted hot coflow , 2002 .

[13]  Stephen B. Pope,et al.  Lagrangian investigation of local extinction, re-ignition and auto-ignition in turbulent flames , 2008 .

[14]  Robert L. Gordon,et al.  Heat release rate as represented by [OH] × [CH2O] and its role in autoignition , 2009 .

[15]  Matthias Ihme,et al.  Prediction of autoignition in a lifted methane/air flame using an unsteady flamelet/progress variable model , 2010 .

[16]  Robert W. Dibble,et al.  Lifted methane–air jet flames in a vitiated coflow , 2005 .

[17]  C. Duwig,et al.  Large Eddy Simulation of a H2/N2 Lifted Flame in a Vitiated Co-Flow , 2008 .

[18]  U. Maas,et al.  Monte Carlo PDF modelling of a turbulent natural-gas diffusion flame , 1997 .

[19]  Salvador Navarro-Martinez,et al.  Large eddy simulation of autoignition with a subgrid probability density function method , 2007 .

[20]  S. Sreedhara,et al.  Autoignition in a non-premixed medium: DNS studies on the effects of three-dimensional turbulence , 2002 .

[21]  M. G. Mungal,et al.  Instantaneous flame-stabilization velocities in lifted-jet diffusion flames , 1997 .

[22]  T. Gatski,et al.  Modelling the pressure–strain correlation of turbulence: an invariant dynamical systems approach , 1991, Journal of Fluid Mechanics.

[23]  A. Masri,et al.  Turbulent lifted flames in a vitiated coflow investigated using joint PDF calculations , 2005 .

[24]  C. Angelberger,et al.  On the formulation of species reaction rates in the context of multi-species CFD codes using complex chemistry tabulation techniques , 2010 .

[25]  Ramanan Sankaran,et al.  Three-dimensional direct numerical simulation of a turbulent lifted hydrogen jet flame in heated coflow: flame stabilization and structure , 2009, Journal of Fluid Mechanics.

[26]  T. Gautam,et al.  Lift-Off Heights and Visible Lengths of Vertical Turbulent Jet Diffusion Flames in Still Air , 1984 .

[27]  D. Roekaerts,et al.  Role of entrainment in the stabilisation of jet-in-hot-coflow flames , 2011 .

[28]  Stephen B. Pope,et al.  Computationally efficient implementation of combustion chemistry using in situ adaptive tabulation , 1997 .

[29]  Yongmo Kim,et al.  DQMOM based PDF transport modeling for turbulent lifted nitrogen-diluted hydrogen jet flame with autoignition , 2012 .

[30]  E. Mastorakos,et al.  Transported scalar PDF calculations of autoignition of a hydrogen jet in a heated turbulent co-flow , 2008 .

[31]  D. Roekaerts,et al.  Ignition kernel formation and lift-off behaviour of jet-in-hot-coflow flames , 2010 .

[32]  D. Veynante,et al.  Using the tabulated diffusion flamelet model ADF-PCM to simulate a lifted methane–air jet flame , 2009 .

[33]  R. Sotudeh-Gharebagh,et al.  Analysis of autoignition of a turbulent lifted H2/N2 jet flame issuing into a vitiated coflow , 2013 .

[34]  Andreas Kronenburg,et al.  LES–CMC simulations of a lifted methane flame , 2009 .

[35]  S. Pope.  PDF methods for turbulent reactive flows , 1985 .

[36]  Ivar S. Ertesvåg,et al.  A NUMERICAL INVESTIGATION OF A LIFTED H2/N2 TURBULENT JET FLAME IN A VITIATED COFLOW , 2006 .

[37]  A. Masri,et al.  Pdf calculations of turbulent lifted flames of H2/N2 fuel issuing into a vitiated co-flow , 2004 .

[38]  C. Markides,et al.  An experimental study of hydrogen autoignition in a turbulent co-flow of heated air , 2005 .

[39]  Robert L. Gordon,et al.  A numerical study of auto-ignition in turbulent lifted flames issuing into a vitiated co-flow , 2007 .

[40]  T. Poinsot,et al.  Numerical simulations of autoignition in turbulent mixing flows , 1997 .

[41]  James F. Driscoll,et al.  Liftoff of turbulent jet flames - Assessment of edge flame and other concepts using cinema-PIV , 2004 .

[42]  B. N. Raghunandan,et al.  CMC simulations of lifted turbulent jet flame in a vitiated coflow , 2009 .

[43]  Stephen B. Pope,et al.  PDF modeling of a bluff-body stabilized turbulent flame , 2003 .

[44]  Jacqueline H. Chen,et al.  Direct numerical simulation of autoignition in non- homogeneous hydrogen-air mixtures , 2003 .

[45]  Salvador Navarro-Martinez,et al.  Flame Stabilization Mechanisms in Lifted Flames , 2011 .

[46]  Simulation of Hydrogen Auto-Ignition in a Turbulent Co-flow of Heated Air with LES and CMC Approach , 2011 .

[47]  J. Janicka,et al.  A detailed investigation of the stabilization point of lifted turbulent diffusion flames , 1998 .

[48]  T. Shih,et al.  A new k-ϵ eddy viscosity model for high reynolds number turbulent flows , 1995 .

[49]  Denis Veynante,et al.  Large-eddy simulation of a lifted methane jet flame in a vitiated coflow , 2008 .

[50]  N. Peters,et al.  The stabilization mechanism and structure of turbulent hydrocarbon lifted flames , 2005 .

[51]  Robert L. Gordon,et al.  Transport budgets in turbulent lifted flames of methane autoigniting in a vitiated co-flow , 2007 .

[52]  Bassam A. Younis,et al.  Assessment of the SSG Pressure-Strain Model in Free Turbulent Jets With and Without Swirl , 1996 .

[53]  Zhenwei Zhao,et al.  An updated comprehensive kinetic model of hydrogen combustion , 2004 .

[54]  E. Mastorakos.  Ignition of turbulent non-premixed flames , 2009 .

[55]  Kevin M. Lyons,et al.  Toward an understanding of the stabilization mechanisms of lifted turbulent jet flames: Experiments , 2007 .

[56]  Analysis of auto-ignition of heated hydrogen–air mixtures with different detailed reaction mechanisms , 2011 .

[57]  S. Sreedhara,et al.  Direct numerical simulation of autoignition in a non-premixed, turbulent medium , 2000 .

[58]  Chung King Law,et al.  Ignition in nonpremixed counterflowing hydrogen versus heated air: Computational study with detailed chemistry , 1996 .

[59]  Stephen B. Pope,et al.  Local Time-Stepping Algorithm for Solving Probability Density Function Turbulence Model Equations , 2002 .