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Building and Fire Research Laboratory

Diffusion Flame Measurements

Profiles in steady and flickering methane/air, ethylene/air, and propane/air
diffusion flames at atmospheric pressure using an axisymmetric burner geometry:

Profiles of soot concentrations (soot volume fraction) as well as some temperature (K) and velocity (cm/s) results are presented for both steady and flickering flame conditions. The burner used in these studies was a duplicate of that employed by R.J. Santoro - see K.C. Smyth, J.E. Harrington, E.L. Johnsson, and W.M. Pitts, Combustion and Flame 95:229-239 (1993) and R.J. Santoro, H.G. Semerjian, and R.A. Dobbins, Combustion and Flame 51:203-218 (1983). A complete listing of literature citations is also included.

Each file contains a header, followed by two or more columns - the first of which is always the lateral position (in mm) versus the soot volume fraction, temperature, or velocity.

(1) Steady Flames

Methane

Three different fuel flow conditions were used, designated by the file suffix. This suffix indicates the cold flow, area-averaged fuel velocity at the exit of the fuel tube in mm/s. For example,

CH4-S-40 signifies:
Methane fuel
[CH4]

Soot measurements
[-S]

Fuel velocity = 40 mm/s
[-40]

CH4-S-40 Visible flame height = 38 mm
H = 15-35 mm, 5 heights

CH4-S-78 Visible flame height = 79 mm
H = 20-75 mm, 12 heights

CH4-S-101 Visible flame height = 107 mm
H = 15-105 mm, 19 heights

Ethylene

Four different fuel flows:

C2H4-S-40 Visible flame height = 88 mm
H = 10-80 mm, 9 heights

C2H4-S-41 Visible flame height = 91 mm
H = 15-90 mm, 16 heights

C2H4-S-46 Visible flame height = 110 mm
H = 10-100 mm, 19 heights

C2H4-S-48 Smoking flame
H = 10-115 mm, 22 heights

Propane

One fuel flow:

C3H8-S-27 Visible flame height = 85 mm
H = 10-75 mm, 14 heights

Measurement uncertainties. For the soot measurements a detailed discussion of data collection and analysis methods (using extinction and laser-induced incandescence) as well as the measurement uncertainties can be found in C.R. Shaddix and K.C. Smyth, Combustion and Flame 107:418-452 (1996). This paper is included here as a PDF file, SOOT-LII.pdf. Note that the laser-induced incandescence measurements were calibrated against extinction results using m = 1.57 - 0.56i as the refractive index of soot.

(1.a) Santoro Profiles

Four of the steady flames listed above closely match conditions used by Bob Santoro and co-workers at Penn State and in our collaborative investigations with this group.

CH4-S-78	R. Puri, M. Moser, R.J. Santoro, and K.C. Smyth, Twenty-Fourth Symposium (International) on Combustion, pp. 1015-1022 (1992).
CH4-S-101	R. Puri, R.J. Santoro, and K.C. Smyth, Combustion and Flame 97:125-144 (1994).
C2H4-S-40, C2H4-S-46	These are designated as the ethylene Non-Smoking (NS) and Incipient-Smoking (IS) flames, respectively, in R.J. Santoro, H.G. Semerjian, and R.A. Dobbins, Combustion and Flame 51:203-218 (1983) and in subsequent papers.

Also included are profiles of temperature and velocity (horizontal and vertical components) measured by Santoro and co-workers for some of these methane/air and ethylene/air flames (T.F. Richardson and R.J. Santoro, personal communication, 1993). Radiation corrections have been made for the thermocouple temperature data, but corrections for thermophoretic effects have not been made in the velocity profiles. Although identical burners were used in the two laboratories, our flames were unconfined, whereas a chimney was utilized by Santoro and co-workers. This may alter the flow fields. The Santoro files (saved in Microsoft Excel 5.0 format) are labelled as follows:

CH4#1-T	corresponds to our CH4-S-78 flame,
CH4#2-T, CH4#2-V	corresponds to our CH4-S-101 flame, and
C2H4NS-T, C2H4NS-V	corresponds to our C2H4-S-40 flame.

(2) Flickering Flames

Soot volume fraction measurements are presented for two flickering conditions, termed moderate (m) and vigorous (v); see C.R. Shaddix and K.C. Smyth, Combustion and Flame 107:418-452 (1996). Profiles were obtained at H = 10-115 mm (22 heights) for methane, ethylene, and propane fuels with a mean fuel flow rate corresponding to our steady CH4-S-78, C2H4-S-40, C3H8-S-27 flames, respectively. (These files are saved in Microsoft Excel 5.0 format.)

Methane	Moderate CH4-75M	Vigorous CH4-150V
Ethylene	Moderate C2H4-75M	Vigorous C2H4-150V
Propane	Moderate C3H8-75M	Vigorous C3H8-150V

Thin-filament pyrometry (TFP) temperature profiles for T > 1200 K are also presented for one phase of the moderately flickering methane flame (60% phase). The experimental approach and uncertainties are discussed in W.M. Pitts, Twenty-Sixth Symposium (International) on Combustion, pp. 1171-1179 (1996) and W.M. Pitts, K.C. Smyth, and D.A. Everest, Twenty-Seventh Symposium (International) on Combustion, pp. 563-569 (1998). The first paper is included here as a PDF file, TEMP-TFP.pdf. These temperature files are labelled as follows:

	Methane fuel [CH4]
	Moderately flickering conditions [m]
*CH4m60-T.xx signifies:*	60% phase [60]
	Temperature [-T]
	Height above the burner exit in mm [.xx]

Also included is the temperature profile used for calibration against thermocouple temperature data at 2000 K. Both profiles were obtained in the steady methane flame with a cold flow velocity of 78 mm/s (the CH4.78 flame). The TFP file (saved in ASCII format) is labelled as

CH4s-T-7.txt

to signify Steady flame temperature data at H = 7 mm.