Multimedia files Nos. 9.1 – 9.10

Chapter 9. Combustion features of the propane round and plane jet at the low Reynolds number

The results of researches presented in presentation are published in the following main articles:

1. G.R. Grek, M.M. Katasonov, V.V. Kozlov, O.P. Korobeinichev, Yu.A. Litvinenko, A.G. Shmakov, Features of the propane combustion in the round and plane macro- and microjet in a transverse acoustic field at small Reynolds number // Vestn. NSU. Seria: Physics. 2013. Vol. 8. Vip. 3, pp. 98-119, in Russian

2. G.R. Grek, Yu.A. Litvinenko V.V. Kozlov, Stability of the subsonic jet flows and combustion // Tutorial, Novosibirsk State University. 2013, pp. 1-239, in Russian

3. Victor V. Kozlov, Genrich R. Grek, Alexander V. Dovgal, Yury A. Litvinenko, Stability of the Subsonic Jet Flows. // Journal of Flow Control, Measurement & Visualization (JFCMV), 2013, Vol. 3, Issue 1, P. 94-101.

4. Victor V. Kozlov, Genrich R. Grek, Mikchail M. Katasonov, Oleg P. Korobeinichev, Yury A. Litvinenko, Andrey G. Shmakov, Stability of Subsonic Microjet Flows and Combustion. // Journal of Flow Control, Measurement & Visualization (JFCMV), 2013, Vol. 3, Issue 1, pp. 108-111.

5. Yu.A. Litvinenko, G.R. Grek, V.V. Kozlov, G.V. Kozlov, Subsonic Round and Plane Macro - and Micro - Jets in a Transverse Acoustic Field // Doklady Physics, 2011. Vol. 56, No. 1, pp. 26-31

Nozzle diameter 5 mmJet velocity 5 ÷ 10 m/sReynolds number 1666 ÷ 3333

Diffusion combustion of the propane round jet with the top – hat mean velocity profile at the nozzle exit

Experimental set – up (top - hat mean velocity profile)

Patterns of the laminar and turbulent propane round macrojet combustion with a top – hat mean velocity profile at

the nozzle exit

Video file No. 9.1 Double click here

Experimental set – up (parabolic mean velocity profile)

Patterns of the laminar and turbulent propane round macrojet combustion with a parabolic mean velocity profile at

the nozzle exit

Double click here

Video file No. 9.2

Diffusion combustion of the propane round microjet under acoustic effect

Nozzle diameters 1, 0.5 mmJet velocity 16.6, 12.5 m/sReynolds number 1110 ÷ 417

Experimental set - up (parabolic mean velocity profile)

Round micro - jet in a transverse acoustic field (flame jet flattening)

Double click hereFlame flattening under action

of the acoustic effectRound jet flattening under action of the acoustic effect (f = 40 (a), 100 (b)

Hz

k - Sinusoidal oscillations scheme of the round jet flattening under action of acoustics

Video file No. 9.3 Double click here

Round microjet in a transverse acoustic field (free jet and flame jet bifurcation)

Round jet bifurcation under action of the acoustic effect

Flame bifurcation under action of the acoustic effect (nozzle diameter 1 mm)

Double click here Video file No. 9.4

Flame bifurcation under action of the acoustic effect (nozzle diameter 0.5 mm)

Double click here Video file No. 9.5

Attached to nozzle flame without acoustic effect (nozzle diameter 0.5 mm)

Video file No. 9.6Double click here

Bifurcation of the lifted flame under acoustic effect (nozzle diameter 0.5 mm)

Diffusion combustion of the propane plane microjet under acoustic effect

Plane microjet (nozzle number 1) in a transverse acoustic field at the diffusion combustion of a propane (flame jet bifurcation)

Nozzle slot width 200 mNozzle slot length 2 mm Jet velocity 20.8, 30.2 m/sReynolds number 277, 426

Experimental set – up (nozzle number 1)

Plane jet flame broadening and bifurcation under action of the acoustic effect

Lifted flame bifurcation under action of the acoustic effect (nozzle width 200 m)

Attached to nozzle flame

(nozzle width 200 m)

Video file No. 9.7Double click here

Broadening and bifurcation of the lifted flame under acoustic effect (nozzle width 200 m)

Plane microjet (nozzle number 2) in a transverse acoustic field at the diffusion combustion of a propane (flame jet bifurcation)

Diffusion combustion of the propane plane microjet under acoustic effect

Nozzle slot width 200 mNozzle slot length 36 mmJet velocity 16 m/sReynolds number 213

Experimental set – up (nozzle number 2)

Flame in yz plane Scheme of experiment

Smoke visualization pattern of the plane jet under acoustic effect (jet twisting)

Video file No. 9.8 Double click here

Broadening and bifurcation of the detached from nozzle flame under acoustic effect (nozzle width 200 m)

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Flame in yz plane (nozzle length 36 mm)

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Flame in xz plane

Smoke visualization pattern of the plane jet under acoustic effect (jet bifurcation)

Video file No. 9.9 Double click hereDouble click

here

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Flame in xz plane (nozzle width 200 m)

Plane micro - jet (nozzle number 1) in a transverse acoustic field at the kinetic combustion of a propane (flame jet bifurcation)Propane (C3H8) / air mixture is 37.2 % / 62.8 %, respectively,

factor of fuel surplus φ = 14

Nozzle slot width 200 mNozzle slot length 2 mm Jet velocity 14 m/sReynolds number 186

Premixed propane/air mixture combustion in the plane microjet under acoustic effect

Plane micro - jet (nozzle number 1) in a transverse acoustic field at the kinetic combustion of a propane (flame jet bifurcation)

Propane (C3H8) / air mixture is 37.2 % / 62.8 %, respectively,factor of fuel surplus φ = 14

Patterns of the premixed propane/air mixture combustion (flame jet bifurcation), U0 14 m/sec, Reh = U0 h/ = 186

Video file No. 9.10 Double click here

Flame bifurcation of the premixed propane/air mixture combustion in xz plane (nozzle number 1, width 200 m)

CONCLUSIONS:

It is found, that diffusion combustion of the laminar round macrojet propane with a top – hat mean velocity profile at the nozzle exit is accompanied by presence of the attached flame developing downstream without any pulsations.

It is shown, that diffusion combustion of the turbulent round macrojet propane is accompanied by the lifted flame, presence of the high-frequency oscillations and the flame broadening.

It is found, that diffusion combustion of the laminar round propane macrojet with a parabolic mean velocity profile at the nozzle exit is accompanied by presence of the attached flame developing downstream without any pulsations.

It is shown, that diffusion combustion of the turbulent round propane macrojet is accompanied by a flame liftoff, presence of the ring vortex on jet butt showing distribution of a flame in narrow area on a jet periphery, jet broadening and presence of the high-frequency pulsations.

It is found, that the flame of round propane microjet combustion is subjected by the flattening and splitting on two jets in a transverse acoustic field.

It is shown, that the lifted flame at diffusion combustion of the round propane microjet in a transverse acoustic field is subjected the flattening and more than three times transverse broadening in comparison with a flame without acoustic influence.

It is revealed, that the detached flame at diffusion combustion of the round propane microjet is subjected to bifurcation due to the break of a sinusoidal oscillation jet on two parts on each half-cycle of its fluctuation in a transverse acoustic field .

It is shown, that process of the flame bifurcation at diffusion combustion of the round propane microjet in a transverse acoustic field can occur both in case of attached and lifted flame.

It is found, that influence of a transverse acoustic field on process of the diffusion and premixed propane/air mixturre combustion of in a plane microjet at the small lengthening nozzle (l/d = 10) results in broadening of combustion area and bifurcation of a flame further downstream.

It is shown, that influence of a transverse acoustic field on process of the diffusion combustion of propane in a plane microjet at the big lengthening nozzle (l/d = 180 results in broadening of combustion area, flame bifurcation and its propagation on a surface of each of two arising jets.

It is found, that the mechanism of a flame round microjets bifurcation is connected with the round jet flattening in a transverse acoustic field that results in two dimensional character of a jet development and impossibility of an explanation of the bifurcation jet phenomenon within the framework of the rotating moment effect (baroclinic torque).