A study of partially premixed unconfined propane flames

Journal Article · Fri Apr 01 00:00:00 EST 1994 · Combustion and Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(94)90118-X· OSTI ID:5107650

Roekke, N A; Hustad, J E; Soenju, O K ^[1]

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1. Norwegian Inst. of Tech., Trondheim (Norway)

Unconfined turbulent partially premixed propane/air flames issuing from a straight tube into quiescent air at atmospheric pressure and temperature are investigated. Experiments on lifted flames are performed. Flame height and liftoff are reported together with emission indices for oxides of nitrogen (NO[sub 3]). The degree of partially premixing has been varied between a fuel mass fraction of 1.0 to 0.15. Six different nozzle diameters, d[sub 0], of 3.2, 6, 10, 20.5, 23.3, and 29.5 mm have been used. This resulted in outlet velocities, u[sub 0], varying from 1 to 130 m/s, flame heights up to 2.5 m, Froude numbers, Fr, from 3 to 3 [times] 10[sup 5], and thermal heat releases up to 350 kW. Flame height and liftoff show a strong dependence upon the ratio of the nozzle outlet velocity to the outlet diameter, the Froude number, and the fuel mass fraction Y[sub f]. Both modified, simplified, and newly developed expressions for height, liftoff and NO[sub x] emissions are presented and discussed. All the proposed expressions scale with Y[sub f][sup a]Fr[sup b] or Y[sub r][sup a]f(u[sub 0], d[sub 0]). The emission index for NO[sub x] scales very well with a previously developed expression based on the buoyant flame volume. The agreement between predictions and experimental data is generally good and well within the underlying experimental and theoretical uncertainties. The results from this study contain new data, as very little focus has previously been directed toward lifted partially premixed free flames of this size.

• OSTI ID: 5107650
• Journal Information: Combustion and Flame; (United States), Vol. 97:1; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
NITROGEN OXIDES
CHEMICAL REACTION YIELD
PROPANE
COMBUSTION KINETICS
EXPERIMENTAL DATA
FLAMES
FUEL-AIR RATIO
MORPHOLOGY
ALKANES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
DATA
HYDROCARBONS
INFORMATION
KINETICS
NITROGEN COMPOUNDS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
YIELDS
034000* - Natural Gas- Combustion