Infrared emission from high-temperature H2O(nu2) - A diagnostic for concentration and temperature

A shock tube system was used to produce known concentrations of water at combustion temperatures so that the infrared radiance from a portion of the H 2 O(v 2 ) band could be measured as a function of temperature and wavelength. The resulting data set was used to determine the efficacy of a spectral emission diagnostic for H 2 O temperature and column density at the exit plane of a supersonic combustor. Temporally and spectrally resolved, optically thin infrared emission, at 13 wavelengths between 6.5 and 9.5 μm, was observed from shock-heated H 2 O/N 2 , H 2 /O 2 /N 2 , and H 2 /O 2 /Ar mixtures, at pressures of 1 and 5 atm and temperatures between 1400 and 3000 K. Least-squares analysis of the temperature-dependent intensities for each wavelength channel gave parameters that accurately describe the radiance as a function of wavelength and temperature over the entire temperature range of the measurements. The accuracy to which temperatures and H 2 O column densities can be determined from these parameters was then estimated. Radiometric data were compared with predictions from a widely used band model, corrections for optically thick systems were explored, and the relationship between optically thin radiance and the optical cross section produced. Column densities at which corrections for optical thickness are required were also calculated.

[1]  Ronald K. Hanson,et al.  Scanned- and fixed-wavelength absorption diagnostics for combustion measurements using a multiplexed diode-laser sensor system , 1995 .

[2]  C. Ludwig.  Measurements of the Curves-of-Growth of Hot Water Vapor. , 1971, Applied optics.

[3]  W. T. Rawlins,et al.  An experimental study of supersonic H2-AIR combustion in a shock tunnel flow facility , 1992 .

[4]  P. Andresen,et al.  Sensitive quantum state selective detection of h2o and d2o by (2+1)-resonance enhanced multiphoton ionization , 1986 .

[5]  J. Simons,et al.  Molecular emission from H2O/D2O [Ctilde] 1 B 1 and photodissociation dynamics on the [Btilde] 1 A 1 surface , 1986 .

[6]  A Goldman,et al.  The HITRAN database: 1986 edition. , 1987, Applied optics.

[7]  N. H. Pratt,et al.  Absolute H2Ov2-band intensity obtained from reacting H2 + O2 mixtures behind shock waves , 1970 .

[8]  William J. Kessler,et al.  Diode laser instrumentation for aeropropulsion applications , 1995 .

[9]  R. Hanson,et al.  Two-line instantaneous temperature imaging of NO in a SCRAMJET modelflowfield , 1993 .

[10]  David M. Sonnenfroh,et al.  Measurements of OH and H2O for Reacting Flow in a Supersonic Combusting Ramjet Combustor , 1995 .

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

[12]  J. Warnatz.  Rate Coefficients in the C/H/O System , 1984 .

[13]  James A. Miller,et al.  Mechanism and modeling of nitrogen chemistry in combustion , 1989 .

[14]  P. Andresen,et al.  The C̃→Ã emission in water: Theory and experiment , 1987 .

[15]  C. B. Ludwig,et al.  Handbook of infrared radiation from combustion gases , 1973 .

[16]  Harold Mirels,et al.  TEST TIME IN LOW PRESSURE SHOCK TUBES , 1963 .

[17]  T. Parker,et al.  AN IN-SITU NITRIC OXIDE SENSOR FOR USE IN HIGH TEMPERATURE POWER PLANT EXHAUSTS , 1998 .

[18]  G. Herzberg,et al.  Molecular Spectra and Molecular Structure: I. Spectra of Diatomic Molecules , 1944 .

[19]  T. Parker,et al.  High-temperature supersonic combustion testing with optical diagnostics , 1993 .

[20]  T. Parker,et al.  Observations of H2O formation in the supersonic combustion of H2 by high-enthalpy air , 1996 .

[21]  Ronald K. Hanson,et al.  Scanned- and fixed-wavelength absorption diagnostics for combustion measurements using multiplexed diode lasers , 1996 .

[22]  T. Parker,et al.  Time-resolved infrared emission spectroscopy in high-enthalpy supersonic air flows , 1993 .