Experimental investigations on temperature profile and air entrainment of buoyancy-controlled jet flame from inclined nozzle bounded the wall

An experimental investigation is described of the microstructure of a flat, premixed, fuel-rich hydrogen+oxygen+nitrogen flame at atmospheric pressure. The study involved measurement of the temperature profile and the concentration profiles for the stable species in the flame. By measuring the profile of emitted light intensity when traces of certain inorganic salts were added to the gases entering the flame, it was further possible to derive information about relative hydrogen atom concentrations in the burnt-gas region.

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Computation of Nitric Oxide and Soot Emissions From Turbulent Diffusion Flames

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.3239696 ◽

1985 ◽

Vol 107 (1) ◽

pp. 48-53 ◽

Cited By ~ 4

Author(s):

T. Ahmad ◽

S. L. Plee ◽

J. P. Myers

Keyword(s):

Diffusion Flames ◽

Soot Oxidation ◽

Air Entrainment ◽

Reaction Rates ◽

Gas Jet ◽

Maximum Temperature ◽

Injection Velocity ◽

Soot Emission ◽

No Emission ◽

Jet Flame

An existing steady-state, locally homogeneous flow model of turbulent spray combustion was modified to predict NO emission from a spray flame and soot emission from a gas-jet flame. The effect of turbulent fluctuations on the reaction rates was accounted for. The predicted NO emission from an n-pentane spray with a changing injection velocity could be correlated with the convective time scale of the flow. Calculation of soot emission from a burning turbulent gas jet indicated that the centerline soot concentration reaches a peak upstream of the maximum temperature location and then decreases due to soot oxidation and dilution by air entrainment.

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Orifice Diameter Effects on Diesel Fuel Jet Flame Structure

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.1760525 ◽

2005 ◽

Vol 127 (1) ◽

pp. 187-196 ◽

Cited By ~ 47

Author(s):

Lyle M. Pickett ◽

Dennis L. Siebers

Keyword(s):

Diesel Fuel ◽

Direct Injection ◽

Flame Structure ◽

Air Entrainment ◽

Flame Length ◽

Turbulent Flames ◽

Orifice Diameter ◽

Jet Flame ◽

Fuel Jet ◽

Lift Off

The effects of orifice diameter on several aspects of diesel fuel jet flame structure were investigated in a constant-volume combustion vessel under heavy-duty direct-injection (DI) diesel engine conditions using Phillips research grade #2 diesel fuel and orifice diameters ranging from 45 μm to 180 μm. The overall flame structure was visualized with time-averaged OH chemiluminescence and soot luminosity images acquired during the quasi-steady portion of the diesel combustion event that occurs after the transient premixed burn is completed and the flame length is established. The lift-off length, defined as the farthest upstream location of high-temperature combustion, and the flame length were determined from the OH chemiluminescence images. In addition, relative changes in the amount of soot formed for various conditions were determined from the soot incandescence images. Combined with previous investigations of liquid-phase fuel penetration and spray development, the results show that air entrainment upstream of the lift-off length (relative to the amount of fuel injected) is very sensitive to orifice diameter. As orifice diameter decreases, the relative air entrainment upstream of the lift-off length increases significantly. The increased relative air entrainment results in a reduced overall average equivalence ratio in the fuel jet at the lift-off length and reduced soot luminosity downstream of the lift-off length. The reduced soot luminosity indicates that the amount of soot formed relative to the amount of fuel injected decreases with orifice diameter. The flame lengths determined from the images agree well with gas jet theory for momentum-driven nonpremixed turbulent flames.

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Effects of Jet Reynolds Number on the Performance of Axisymmetric and Nonaxisymmetric Gas Burner Flames

Volume 2: 19th Computers and Information in Engineering Conference ◽

10.1115/detc99/cie-9055 ◽

1999 ◽

Author(s):

Azfar Kamal ◽

S. R. Gollahalli

Keyword(s):

Reynolds Number ◽

Heat Release ◽

Flame Temperature ◽

Air Entrainment ◽

Flame Length ◽

Temperature Profiles ◽

Jet Flame ◽

Burner Exit ◽

Equivalent Area ◽

Emission Index

Abstract An investigation of the effects of burner exit Reynolds number (9,400–19,000) on the relative effects of burner geometry (circular and elliptic with an aspect ratio 2–4) in a propane jet flame is presented. Circular and elliptic burners of the equivalent area of a circular burner of diameter 5.02 mm were studied. Air entrainment into the nonreacting jets, emission indices of NO, NO2, and CO, visible flame length, flame temperature profiles, radiative fraction of heat release, and soot concentration were measured. Results show that an increase in Re decreases the benefits of higher air entrainment into the flame due to elliptic burner geometry. Similarly, the effects of changes in NO and CO emission indices level off at higher burner Re. The measurements of visible flame length, radiative fraction flame heat release, temperature profiles, and soot concentrations corroborate and offer the explanations for the observed emission index results.

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Temperature Profile of Thermal Impinging Flow Induced by Horizontally Oriented Rectangular Jet Flame Upon an Opposite Plate

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4043469 ◽

2019 ◽

Vol 11 (5) ◽

Author(s):

Bingyan Dong ◽

Youbo Huang ◽

Jinxiang Wu

Keyword(s):

Aspect Ratio ◽

Temperature Profile ◽

Vertical Temperature ◽

Jet Flame ◽

Opposite Wall ◽

Aspect Ratios ◽

Fuel Jet ◽

Jet Velocity ◽

Jet Velocities ◽

Impinging Flow

The horizontally oriented jet flame induced by rectangular source impinging upon the opposite wall is actually common in the chemical industry, but the related studies are limited. In this paper, the computational fluid dynamics codes are carried out to investigate the temperature profile in thermal impinging flow of the horizontally oriented methane jet flame with rectangular source, which the rectangular orifice is 400 mm2 with three different aspect ratios (L/W = 1, 2, 4); besides, the jet velocities vary from 27.5 m/s to 125 m/s. As the horizontally oriented methane jet flame impinges on the vertical plate in front of the fuel orifice directly, the vertical temperature along the opposite plate is focused on. Results show that the temperature near the impingement point is the same for different jet velocities, but the temperature along the vertical direction is larger with increasing fuel jet velocity. Moreover, the orifice aspect ratio has a significant effect on the temperature, which increases with the aspect ratio at a given position for the momentum-controlled flame. The effective heat release rate on the basis of unburned fuel and ellipse flame shape hypothesis is put forward to correlate the temperature profile. Finally, a new correlation to illustrate the vertical temperature rising along the opposite plate is proposed in light of the orifice aspect ratio and fuel jet velocity, and the predictions obtained by the proposed model agree well with the numerical results, which is applicable for the horizontally oriented flame with rectangular source impinging upon the opposite wall.

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