Response of a stretched cylindrical diffusion flame  to a sinusoidal velocity oscillation of air stream

In the present study, the combustion characteristics of LPG gaseous fuel diffusion flame at elevated air temperatures were experimentally investigated. An experimental test rig was manufactured to examine a wide range of operating conditions. The investigated parameters are the air temperatures of 300, 350, 400, 450, and 500 K with constant percentage of nitrogen addition in combustion air stream of 5 % to give low oxygen concentration of 18.3 % by mass at constant air swirl number, air to fuel mass ratio, and thermal load of 1.5, 30, and 23 kW, respectively. The gaseous combustion characteristics were represented as axial and radial temperatures distributions, temperatures gradient, visible flame length and species concentrations. The results indicated that as the air temperature increased, the chemical reaction rate increased and flame volume decreased, the combustion time reduced leading to a reduction in flame length. The NO concentration reaches its maximum values near the location of the maximum centerline axial temperature. Increasing the combustion air temperature by 200 K, the NO consequently O2 concentrations are increased by about % 355 and 20 % respectively, while CO2 and CO concentrations are decreased by about % 21 and 99 % respectively, at the combustor end.

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Thermal and Scalar Dissipation Rates of Stretched Cylindrical Diffusion Flame

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B ◽

10.1299/kikaib.79.1685 ◽

2013 ◽

Vol 79 (804) ◽

pp. 1685-1693 ◽

Cited By ~ 2

Author(s):

Yosuke SUENAGA ◽

Hideki YANAOKA ◽

Michio KITANO ◽

Daisuke MOMOTORI

Keyword(s):

Diffusion Flame ◽

Scalar Dissipation ◽

Dissipation Rates ◽

Cylindrical Diffusion

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An Experimental Investigation of the Blowout Limits of a Jet Diffusion Flame in Co-Flowing Streams of Different Velocity and Composition

Journal of Energy Resources Technology ◽

10.1115/1.2905981 ◽

1993 ◽

Vol 115 (2) ◽

pp. 142-147 ◽

Cited By ~ 5

Author(s):

I. Wierzba ◽

K. Kar ◽

G. A. Karim

Keyword(s):

Carbon Dioxide ◽

Experimental Investigation ◽

Laminar Flow ◽

Turbulent Flow ◽

Diffusion Flame ◽

Detrimental Effect ◽

Stream Velocity ◽

Air Stream ◽

Methane Diffusion ◽

Flow Stream

The blowout limits of a methane diffusion flame in a co-flowing air-fuel or air-diluent stream were determined for a range of surrounding co-flow stream velocities, both laminar and turbulent, up to ~ 1.50 m/s. Methane, ethylene, propane and hydrogen were used as the fuels in the surrounding co-flow stream while nitrogen and carbon dioxide were used as diluents. The experimental results show that the velocity of the surrounding stream affects the blowout phenomena significantly. An increase in the stream velocity has a detrimental effect on the blowout limits at very low velocities up to 0.30 m/s (essentially laminar flow) and at velocities higher than 1.50 m/s (turbulent flow). The addition of a fuel to the air stream in most cases enhances the blowout limit of a methane diffusion flame. However, different trends in the variation of the blowout limits with the surrounding fuel concentration were observed, depending on the type of fuel used and on whether the surrounding coflow stream was laminar or turbulent. The addition of nitrogen or carbon dioxide to the air stream results in decreasing the blowout limits. The effect is more severe at the higher velocities.

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