Planar laser-induced-fluorescence imaging measurements of OH and hydrocarbon fuel fragments in high-pressure spray-flame combustion.

Planar laser-induced fluorescence images of OH have been obtained in liquid-fueled spray flames burning heptane, ethanol, and methanol over a range of pressures from 0.1 to 1.0 MPa. In addition to the OH fluorescence, a nonresonant fluorescence interference that increased rapidly with pressure was detected. Examination of the spectrum of this interference indicates that it arises from hydrocarbon fuel-fragment species in the fuel-rich zones of the flame. The pressure dependence of the fluorescence signal is examined in both steady-state and time-dependent analyses, and a model for evaluation of pressure effects and quenching variations in quantitative imaging measurements in nonpremixed flame environments is presented. The results indicate that increased combustor pressure results in a rapid rise of the volume fraction of hydrocarbon fragments and a decrease in the OH volume fraction.

[1]  P. Paul.  A model for temperature-dependent collisional quenching of OHA2∑+ , 1994 .

[2]  C. Carter,et al.  Measurements and modeling of flamefront no formation and superequilibrium radical concentrations in laminar high-pressure premixed flames , 1991 .

[3]  P. Andresen,et al.  Fluorescence imaging inside an internal combustion engine using tunable excimer lasers. , 1990, Applied optics.

[4]  R. Howe,et al.  Digital imaging of reaction zones in hydrocarbon - air flames using planar laser-induced fluorescence of CH and C2. , 1986, Optics letters.

[5]  S. Davis,et al.  Species and temperature imaging in liquid-fueled spray flames , 1990 .

[6]  J. Troe,et al.  Shock wave study of benzyl UV absorption spectra: Revised toluene and benzyl decomposition rates , 1988 .

[7]  A. Ciajolo,et al.  Axial and radial measurements of soot and pah in a light oil flame , 1982 .

[8]  W. Kessler,et al.  Rotational level-dependent collisional broadening and line shift of the A2σ+−X2∏ (1, 0) band of OH in hydrogen-air combustion gases , 1993 .

[9]  K. Mcmanus,et al.  PLIF imaging measurements in high-pressure spray flame combustion , 1994 .

[10]  J. Troe,et al.  UV absorption spectra of vibrationally highly excited toluene molecules , 1983 .

[11]  A Arnold,et al.  Flame front imaging in an internal-combustion engine simulator by laser-induced fluorescence of acetaldehyde. , 1990, Optics letters.

[12]  P. Andresen,et al.  Planar imaging of a laboratory flame and of internal combustion in an automobile engine using UV rayleigh and fluorescence light , 1993 .

[13]  R. Farrow,et al.  Predissociation lifetimes of OH A 2Σ+ (V'=3) obtained from optical-optical double-resonance linewidth measurements , 1991 .

[14]  K. Kohse-Höinghaus,et al.  Measurements of rotational energy transfer and quenching in OHA2σ+,υ′ = 0 at elevated temperature , 1994 .

[15]  R. Santoro,et al.  Laser-induced fluorescence measurements of oh· concentrations in the oxidation region of laminar, hydrocarbon diffusion flames , 1992 .

[16]  U. Meier,et al.  Laser-induced fluorescence study of OH in flat flames of 1-10 bar compared with resonance CARS experiments. , 1990, Applied optics.

[17]  R. Hanson,et al.  Quantitative planar laser-induced fluorescence imaging of radical species in high pressure flames , 1994 .

[18]  Robert J. Santoro,et al.  Soot inception in a methane/air diffusion flame as characterized by detailed species profiles , 1985 .

[19]  J. Jeffries,et al.  Collisional energy transfer in predissociative OH laser-induced fluorescence in flames. , 1993, Optics letters.

[20]  C. Bowman,et al.  Soot production in axisymmetric laminar diffusion flames at pressures from one to ten atmospheres , 1988 .

[21]  F. Cignoli,et al.  A complete treatment of a steady-state four-level model for the interpretation of OH laser-induced fluorescence measurements in atmospheric pressure flames , 1990 .

[22]  N. Laurendeau,et al.  Saturated-Fluorescence Measurements of the Hydroxyl Radical , 1980 .

[23]  J. Longwell,et al.  The effect of ethylene and benzene addition on the formation of polycyclic aromatic hydrocarbons and soot in a jet-stirred/plug-flow combustor , 1991 .

[24]  F. Cignoli,et al.  Simultaneous one-dimensional visualization of OH, polycyclic aromatic hydrocarbons, and soot in a laminar diffusion flame. , 1992, Optics letters.

[25]  Ronald K. Hanson,et al.  Collisional broadening of the A2Σ+←X2Π(0,0) band of OH by H2O and CO2 in atmospheric-pressure flames , 1989 .

[26]  P. Andresen,et al.  Identification and imaging of OH (nu'' = O) and O(2) (nu'' = 6 or 7) in an automobile spark-ignition engine using a tunable KrF excimer laser. , 1992, Applied optics.

[27]  W. Kessler,et al.  Velocity Field Imaging in Supersonic Reacting Flows near Atmospheric Pressure , 1994 .

[28]  C. Carter,et al.  Laser-induced fluorescence measurements of nitric oxide in laminar C2H6/O2/N2 flames at high pressure , 1993 .

[29]  P. Andresen,et al.  Multi-species detection in spray flames with tunable excimer lasers , 1993 .

[30]  Jerry M. Seitzman,et al.  Comparison of NO and OH planar fluorescence temperature measurements in scramjet model flowfields , 1994 .

[31]  R. Hanson,et al.  Digital imaging of species concentration fields in spray flames , 1988 .

[32]  N. Laurendeau,et al.  Time-resolved fluorescence investigation of rotational transfer in A 2 ∑ + (v = 0) OH , 1986 .

[33]  W. Ketterle,et al.  Laser in situ monitoring of combustion processes. , 1990, Applied optics.

[34]  B. Lüers,et al.  Soot formation in premixed C2H4 flat flames at elevated pressure , 1991 .

[35]  P. Paul.  Vibrational Energy Transfer and Quenching of OH A2.SIGMA.+(.nu.'=1) Measured at High Temperatures in a Shock Tube , 1995 .

[36]  W. T. Rawlins,et al.  Fluorescence imaging of OH and NO in a model supersonic combustor , 1993 .