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Building and Fire Research Laboratory

Diffusion Flame Measurements

Profiles in the methane/air diffusion flame at atmospheric pressure using the
Wolfhard-Parker burner, 2-D rectilinear geometry:

Profiles of species concentrations (mole fraction), temperature (K), and velocity (cm/s) are presented, as well as profiles of the mixture fraction and scalar dissipation rate. Species include Ar, CH, CH₃, C₂H₂, C₆H₆, CH₂O, CH₄, CO, CO₂, H₂, H₂O, H atom, N₂, NO, O₂, and O atom. A complete listing of literature citations is also included.

Each file contains one line of header, followed by two or more columns - lateral position (in mm) versus concentration, temperature, or velocity at one or more heights above the burner surface. The file label specifies the particular species, and "B" indicates our best data. When a file contains information at only one height, this height is also indicated - i.e., "-B9" stands for best data at 9 mm above the burner. In this best data set, all of the original data files have been centered and symmetrized (left and right hand sides averaged) with respect to the burner centerline. No smoothing has been carried out, except for the velocity files. Radiation corrections have been made for the thermocouple temperature data, but thermophoretic effects have not been included in the velocity profiles.

The original temperature and velocity files are included and designated as "-DAT" files, covering a range of heights above the burner from 3 to 19 mm.

Measurement Uncertainties. A detailed discussion of measurement uncertainties and database consistency checks can be found in T.S. Norton, K.C. Smyth, J.H. Miller, and M.D. Smooke, Combustion Science and Technology 90:1-34 (1993), wherein our experimental results are compared to computations of Smooke. In addition, a discussion of radical concentrations (specifically H atom, O atom, OH, CH, triplet CH₂, and CH₃) has been presented in K.C. Smyth, Combustion Science and Technology 115:151-176 (1996). Both of these papers are included here as PDF files, COMPARISON.pdf and NO ANALYSIS.pdf.

Most of the data files are for heights of 7, 9, and 11 mm. This has been a convenient region in which to analyze hydrocarbon chemistry because the concentrations of acetylenic and aromatic hydrocarbons are appreciable, yet significant amounts of soot have not yet formed. With a reasonably complete set of species concentrations, as well as data on temperatures and velocities, two types of analyses have been carried out: (1) net production and destruction rates and (2) reaction rates for specific elementary steps. The particular species are listed below:

C₂H₂, C₄H₆, and C₆H J.H. Miller, W.G. Mallard, and K.C. Smyth, Twenty-First Symposium (International) on Combustion,
pp. 1057-1065 (1986) and K.C. Smyth and J.H. Miller, Science 236:1540-1546 (1987).

CH₃ J.H. Miller and P.H. Taylor, Combustion Science and Technology 52:139-149 (1987).

OH K.C. Smyth, P.J.H. Tjossem, A. Hamins, and J.H. Miller, Combustion and Flame 79:366-380 (1990).

CH T.S. Norton and K.C. Smyth, Combustion Science and Technology 76:1-20 (1991).

NO K.C. Smyth, Combustion Science and Technology 115:151-176 (1996).

Benzene concentration:

Since the original paper was written on profile measurements [K.C. Smyth, J.H. Miller, R.C. Dorfman, W.G. Mallard, and R.J. Santoro, Combustion and Flame 62:157-181 (1985)], our toluene calibration procedure has been found to be in error because a significant M-1 daughter ion peak was not taken into account [see Fig. 2 of A. Hamins, D.T. Anderson, and J.H. Miller, Combustion Science and Technology 71:175-195 (1990)]. This results in a lower maximum benzene concentration. Our revised estimate of the peak concentration at H = 9 mm is 450 ppm with an uncertainty of " 40%. This value is somewhat higher than that given in Table I of the Hamins et al. paper. There may also be an additional systematic error, since Phil Westmoreland has reported that only 72% of the mass 78 peak was due to benzene in similar mass spectrometric experiments [P.R. Westmoreland, A.M. Dean, J.B. Howard, and J.P. Longwell, Journal of Physical Chemistry 93:8171 (1989)].

Other hydrocarbon concentrations:

Profiles of C₄H₂ and C₄H₆ are reported in K.C. Smyth, J.H. Miller, R.C. Dorfman, W.G. Mallard, and R.J. Santoro, Combustion and Flame 62:157-181 (1985). Peak concentrations for additional hydrocarbon species are given by A. Hamins, D.T. Anderson, and J.H. Miller, Combustion Science and Technology 71:175-195 (1990) - see their Table I.