350 likes | 368 Views
Dive into the intricate features of propane combustion in round and plane jets under acoustic effects and Reynolds numbers. Witness patterns of laminar and turbulent macrojet combustion, flame flattening, jet bifurcation, and more in this multimedia presentation showcasing experimental setups and visualization studies. Gain insight into stability, flow control, and measurement techniques in subsonic jet flows. This research sheds light on the complexities of diffusion combustion and kinetic combustion phenomena.
E N D
Chapter 9. Combustion features of the propane round and plane jet at the low Reynolds number Multimedia files Nos. 9.1 – 9.10 • The results of researches presented in presentation are published in the following • main articles: • 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 • 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 • 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. • 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
Diffusion combustion of the propane round jet with the top – hat mean velocity profile at the nozzle exit Nozzle diameter5 mmJet velocity 5 ÷10m/sReynolds number 1666 ÷ 3333
Patterns of the laminar and turbulent propane round macrojet combustion with a top – hat mean velocity profile at the nozzle exit
Double click here Video fileNo. 9.1
Patterns of the laminar and turbulent propane round macrojet combustion with a parabolic mean velocity profile at the nozzle exit
Video fileNo. 9.2 Double click here
Diffusion combustion of the propane round microjet under acoustic effect Nozzle diameters1, 0.5 mmJet velocity16.6, 12.5m/sReynolds number 1110 ÷ 417
Round micro - jet in a transverse acoustic field(flamejet flattening)
Double click here Flame flattening under action of the acoustic effect Round 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
Double click here Video fileNo. 9.3
Round microjet in a transverse acoustic field(free jet andflame jet bifurcation)
Flame bifurcation under action of the acoustic effect (nozzle diameter 1 mm)
Double click here Video fileNo. 9.4
Flame bifurcation under action of the acoustic effect (nozzle diameter 0.5 mm)
Double click here Video fileNo. 9.5 Attached to nozzle flame without acoustic effect (nozzle diameter 0.5 mm)
Video fileNo. 9.6 Double 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 (flamejet bifurcation) Nozzle slot width200mmNozzle slot length2 mmJet velocity20.8, 30.2m/sReynolds number 277, 426
Plane jet flame broadening and bifurcation under action of the acoustic effect Attached to nozzle flame (nozzle width 200 mm) Lifted flame bifurcation under action of the acoustic effect (nozzle width 200 mm)
Video fileNo. 9.7 Double click here Broadening and bifurcation of the lifted flame under acoustic effect (nozzle width 200 mm)
Diffusion combustion of the propane plane microjet under acoustic effect Plane microjet (nozzle number 2) in a transverse acoustic field at the diffusion combustion of a propane (flamejet bifurcation) Nozzle slot width200mmNozzle slot length36 mmJet velocity16m/sReynolds number 213
Smoke visualization pattern of the plane jet under acoustic effect (jet twisting) Flame in yz plane Scheme of experiment
Video fileNo. 9.8 Double click here Double click here Double click here Broadening and bifurcation of the detached from nozzle flame under acoustic effect (nozzle width 200 mm) Flame in yz plane (nozzle length 36 mm)
Smoke visualization pattern of the plane jet under acoustic effect (jet bifurcation) Flame in xz plane
Video fileNo. 9.9 Double click here Double click here Double click here Flame in xz plane (nozzle width 200 mm)
Premixed propane/air mixture combustionin the plane microjet under acoustic effect Plane micro - jet (nozzle number 1) in a transverse acoustic field at the kinetic combustion of a propane (flamejet bifurcation) Propane (C3H8) / air mixture is 37.2 % / 62.8 %, respectively,factor of fuel surplus φ= 14 Nozzle slot width200mmNozzle slot length2 mmJet velocity14m/sReynolds number 186
Patterns of the premixed propane/air mixture combustion(flamejet bifurcation), U0 14 m/sec, Reh = U0h/n= 186 Plane micro - jet (nozzle number 1) in a transverse acoustic field at the kinetic combustion of a propane (flamejet bifurcation) Propane (C3H8) / air mixture is 37.2 % / 62.8 %, respectively,factor of fuel surplus φ= 14
Double click here Video fileNo. 9.10 Flame bifurcation of the premixed propane/air mixture combustionin xz plane (nozzle number 1, width 200 mm)
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).