ISSN 0010-5082, Combustion, Explosion, and Shock Waves, 2018, Vol. 54, No. 3, pp. 255–263.
Pleiades Publishing, Ltd., 2018.
Original Russian Text
V.V. Lemanov, V.V. Lukashov, R. Kh. Abdrakhmanov, V.A. Arbuzov, Yu.N. Dubnishchev, K.A. Sharov.
Regimes of Unstable Expansion
and Diﬀusion Combustion of a Hydrocarbon Fuel Jet
V. V. Lemanov
, R. Kh. Abdrakhmanov
V. A. Arbuzov
, Yu. N. Dubnishchev
, and K. A. Sharov
Published in Fizika Goreniya i Vzryva, Vol. 54, No. 3, pp. 3–12, May–June, 2018.
Original article submitted September 1, 2017.
Abstract: Results of an experimental study of hydrodynamics and diﬀusion combustion of hydro-
carbon jets are presented. Various regimes of instability development both in the jet ﬂame proper
and inside the source of the fuel jet are considered. The experiments are performed for the case
of subsonic gas jet expansion into the air from a long tube 3.2 mm in diameter in the range of
Reynolds numbers from 200 to 13 500. The fuel is the propane–butane mixture in experiments with
a cold jet (without combustion) and pure propane or propane mixed with an inert dilutant (CO
or He) for the jet ﬂame. The mean velocity and velocity ﬂuctuations in the near ﬁeld of the jet
without combustion are measured. Among four possible regimes of cold jet expansion (dissipative,
laminar, transitional, and turbulent), three last regimes are investigated. The Hilbert visualization
of the reacting ﬂow is performed. The temperature proﬁles in the near ﬁeld of the jet are measured
by a Pt/Pt–Rh thermocouple. An attached laminar ﬂame is observed in the transitional regime
of propane jet expansion from the tube. In the case of combustion of C
mixtures with CO
with He in the range of Reynolds numbers from 1900 to 3500, the transitional regime is detected in
the lifted ﬂame. Turbulent spots formed in the tube in the transitional regime exert a signiﬁcant
eﬀect on the ﬂame front position: they can either initiate a transition to a turbulent ﬂame or lead
to its laminarization.
Keywords: diﬀusion ﬂame, combustion control, subsonic gas jets, laminar–turbulent transition,
vortex structures, turbulence, experiment, visualization.
Control of mixing and combustion processes in jet
ﬂows is an important problem. Devices based on dif-
fusion combustion of hydrocarbon jets are widely used
in power engineering and chemical technologies. This
problem was studied in much detail and was discussed
in the literature . Technology requirements usually
Kutateladze Institute of Thermophysics, Siberian Branch,
Russian Academy of Sciences, Novosibirsk, 630090 Russia;
Novosibirsk State University of Architecture and Civil
Engineering, Novosibirsk, 630008 Russia.
Novosibirsk State Technical University, Novosibirsk,
imply the use of jet sources in the form of holes or con-
toured nozzle, and tubes areusedmoreseldom. The
Reynolds numbers in such gas jets are usually greater
than 4000, and turbulent ﬂow regimes are observed .
Various methods are used to control mixing and com-
bustion: addition of inert gases, coaxial and swirling
jets, vibrational, acoustic, or plasma impacts, etc. One
of the promising methods of ﬂame control is the jet dif-
fusion combustion with instability development in the
jet ﬂame itself and inside the source of jet formation.
Instability of gas jets (without combustion) arises
at low Reynolds numbers (Re = 10–30) and was studied
in much detail [3, 4]. However, the transition to tur-
bulence in jets occurs at signiﬁcantly higher Reynolds
numbers (Re = 500–2000), and there is a lack of exper-
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