Raman/Rayleigh scattering and CO-LIF measurements in laminar and turbulent jet flames of dimethyl ether

Abstract To reduce the impact of combustion of fossil fuels on air quality and climate change, dimethyl ether (DME) is a promising alternative diesel fuel candidate. Technical combustion processes, including formation of pollutants, are influenced by turbulence–chemistry interaction. Therefore, accurate prediction by computational combustion models of combustion systems burning DME must account for multiple scalars and scalar gradients. The testing of such models requires detailed experiments. Here a study is presented on the feasibility of simultaneous species and temperature measurements in turbulent dimethyl ether flames, using line-imaged Raman/Rayleigh scattering of the major species H 2 , O 2 , N 2 , CO, CO 2 , H 2 O, C 2 H 6 O and laser induced fluorescence of CO. The measurement system and data evaluation methods developed to investigate methane–air flames are extended to address dimethyl ether flames. The Raman signal intensity and spectral shape of the Raman scattering from dimethyl ether over a range of temperatures are presented, based on measurements in electrically heated flows and laminar jet flames. These data are used to develop an iterative method for data evaluation that allows determination of indispensable crosstalk correction terms for the concentration measurements of O 2 and CO 2 . Issues of fluorescence interferences, mainly from C 2 radicals on the fuel-rich side of the reaction zone, and their corrections are discussed. Laminar flame calculations are used to investigate the role of the intermediate species (CH 4 , CH 2 O, C 2 H 4 , C 2 H 2 , C 2 H 6 , CH 3 ) in the reaction zone. In particular, their effect on the mixture fraction calculation and its relationship to the experimentally determined mixture fraction is examined. The impact of the intermediate species on deviations in concentration and temperature profiles due to species-specific Raman- and Rayleigh scattering cross-sections is demonstrated. Finally, species concentrations and temperature profiles from measurements in a turbulent piloted jet flame of dimethyl ether are shown.

[1]  N. Bridge,et al.  The polarization of laser light scattered by gases , 1964, Proceedings of the Royal Society of London. Series A, Mathematical and physical sciences.

[2]  Douglas A. Greenhalgh,et al.  A combustion temperature and species standard for the calibration of laser diagnostic techniques , 2006 .

[3]  G. Herzberg,et al.  Molecular spectra and molecular structure. Vol.2: Infrared and Raman spectra of polyatomic molecules , 1945 .

[4]  Thomas Seeger,et al.  Application of 266-nm and 355-nm Nd:YAG laser radiation for the investigation of fuel-rich sooting hydrocarbon flames by raman scattering. , 2004, Applied optics.

[5]  P. Bleckmann,et al.  Calculation of relative Raman intensities: II. Calculations using an extended Hückel valence basis set , 1980 .

[6]  William F. Murphy,et al.  The Rayleigh depolarization ratio and rotational Raman spectrum of water vapor and the polarizability components for the water molecule , 1977 .

[7]  Robert S. Barlow,et al.  Measurements of scalar dissipation in a turbulent piloted methane/air jet flame , 2002 .

[8]  Experimental and numerical study of a highly diluted turbulent diffusion flame close to blowout , 1998 .

[9]  Forman A. Williams,et al.  Laminar flow between parallel plates with injection of a reactant at high reynolds number , 1978 .

[10]  R. Barlow,et al.  Effects of turbulence on species mass fractions in methane/air jet flames , 1998 .

[11]  P. Bruna,et al.  Benchmark ab initio calculations of formaldehyde, H2CO , 1997 .

[12]  Numerical modeling of NO formation in laminar Bunsen flames -- A flamelet approach , 1998 .

[13]  P. Taylor,et al.  On the calculation of dipole moment and polarizability derivatives by the analytical energy gradient method: Application to the formaldehyde molecule , 1984 .

[14]  Robert S. Barlow,et al.  Piloted jet flames of CH4/H2/air: Experiments on localized extinction in the near field at high Reynolds numbers , 2009 .

[15]  W. Meier,et al.  Laser Raman scattering in fuel-rich flames: background levels at different excitation wavelengths , 2002 .

[16]  Walter R. Lempert,et al.  Laser Rayleigh scattering , 2001 .

[17]  Derek A. Long,et al.  The Raman Effect: A Unified Treatment of the Theory of Raman Scattering by Molecules , 2001 .

[18]  Johannes Janicka,et al.  Turbulence modulation in jet diffusion flames: Modeling and experiments , 1996 .

[19]  P. Kelly,et al.  Resonance Raman spectroscopy of the methyl radical , 1988 .

[20]  A. Masri,et al.  The spontaneous raman scattering technique applied to nonpremixed flames of methane , 1987 .

[21]  P. Miles.  Raman line imaging for spatially and temporally resolved mole fraction measurements in internal combustion engines. , 1999, Applied optics.

[22]  C. Dreyer,et al.  Raman scattering at 532 and 355 nm in atmospheric pressure propane/air flames, with and without liquid fuels , 2004 .

[23]  A. E. Fuhs,et al.  Handbook of Fluid Dynamics and Fluid Machinery , 1996 .

[24]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[25]  E. Jourdanneau,et al.  The methane Raman spectrum from 1200 to 5500 cm−1: A first step toward temperature diagnostic using methane as a probe molecule in combustion systems , 2005 .

[26]  B. H. Crichton,et al.  Gas discharge physics , 1996 .

[27]  R. Barlow,et al.  Scalar profiles and NO formation in laminar opposed-flow partially premixed methane/air flames , 2001 .

[28]  F. Dryer,et al.  Thermal decomposition reaction and a comprehensive kinetic model of dimethyl ether , 2008 .

[29]  J. Janicka,et al.  Flow field measurements of stable and locally extinguishing hydrocarbon-fuelled jet flames , 2003 .

[30]  Robert S. Barlow,et al.  Measurements of flame orientation and scalar dissipation in turbulent partially premixed methane flames , 2005 .

[31]  R. S. Barlow,et al.  Raman-Rayleigh-LIF measurements of temperature and species concentrations in the Delft piloted turbulent jet diffusion flame , 2000 .

[32]  R. Barlow,et al.  Piloted methane/air jet flames: Transport effects and aspects of scalar structure , 2005 .

[33]  R. Barlow,et al.  Application of Raman/Rayleigh/LIF diagnostics in turbulent stratified flames , 2009 .

[34]  Robert W. Dibble,et al.  The structure of turbulent nonpremixed flames of methanol over a range of mixing rates , 1992 .

[35]  R. Barlow,et al.  Measurements of Scalar Variance, Scalar Dissipation, and Length Scales in Turbulent Piloted Methane/Air Jet Flames , 2004 .

[36]  W. C. Gardiner,et al.  Refractivity of combustion gases , 1981 .

[37]  D. C. Mckean,et al.  Vibrational spectra of crystalline dimethyl ethers , 1971 .

[38]  R. Barlow,et al.  A hybrid method for data evaluation in 1-D Raman spectroscopy , 2011 .

[39]  Robert J. Kee,et al.  PREMIX :A F ORTRAN Program for Modeling Steady Laminar One-Dimensional Premixed Flames , 1998 .

[40]  A. T. Hartlieb,et al.  Tunable KrF laser-induced fluorescence of C2 in a sooting flame , 1998 .

[41]  R. Rowell,et al.  Rayleigh–Raman Depolarization of Laser Light Scattered by Gases , 1971 .

[42]  W. Ubachs,et al.  Direct measurement of the Rayleigh scattering cross section in various gases , 2005 .

[43]  Robert J. Kee,et al.  On reduced mechanisms for methaneair combustion in nonpremixed flames , 1990 .

[44]  J. Uhlenbusch,et al.  Determination of the absolute Raman cross section of methyl , 1996 .

[45]  D. Stephenson.  Raman cross sections of selected hydrocarbons and freons , 1974 .

[46]  Timothy J. Wallington,et al.  Experimental and Modeling Study of Premixed Atmospheric-Pressure Dimethyl Ether−Air Flames , 2000 .

[47]  V. Boudon,et al.  The vibrational levels of methane obtained from analyses of high-resolution spectra , 2006 .

[48]  C. Altona,et al.  Application of self-consistent-field ab initio calculations to organic molecules: VI. Dimethylether: general valence force field scaled on experimental frequencies, infra-red and Raman intensities , 1977 .

[49]  J. Janicka,et al.  Measurement of temperature and concentration in oxy-fuel flames by Raman/Rayleigh spectroscopy , 2002 .

[50]  A. Mokhov,et al.  Spontaneous Raman measurements of acetylene in atmospheric-pressure methane/air flames , 2005 .

[51]  G. Herzberg,et al.  Molecular Spectra and Molecular Structure , 1992 .

[52]  Allan H. White,et al.  Rayleigh scattering depolarization ratio and molecular polarizability anisotropy for gases , 1978 .

[53]  R. Barlow,et al.  Some raman/rayleigh/lif measurements in turbulent propane flames , 1991 .

[54]  Andrew G. Glen,et al.  APPL , 2001 .

[55]  A. Leipertz,et al.  One-Dimensional, Time-Resolved Raman Measurements in a Sooting Flame made with 355-nm Excitation. , 1998, Applied optics.

[56]  Ranbir Singh,et al.  J. Mol. Struct. (Theochem) , 1996 .

[57]  H. F. Hameka.  Theoretical prediction of structures and infrared frequencies , 1991 .

[58]  Andrew E. Lutz,et al.  OPPDIF: A Fortran program for computing opposed-flow diffusion flames , 1997 .

[59]  Antonio Rizzo,et al.  Linear response coupled cluster calculation of Raman scattering cross sections , 2002 .