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Swirling flame
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EXPERIMENTAL STUDY OF THE FUEL COMBUSTION AND SWIRLING FLAME DYNAMICS
UNDER THE PREMIXED AND NON-PREMIXED COMBUSTION CONDITIONS
The general objective of the research is development and
optimization of
the swirling combustion by providing the control of the swirling flame
flow formation and recirculation of products inside the swirling flame
flow and so providing control of the mixing rates of the axial fuel flow
with the swirling airflow, formation of the temperature field downstream
of the swirling flame flow, as well as control of the formation of
polluting emissions. The electric field effect on the swirling flame
dynamics is used to provide the control of the swirling flame dynamics and
the formation of the polluting emissions. It is established that the
electric force largely (F=qE) affects the axial velocity component of the
swirling flame flow with a direct influence on the recirculation and
swirling flame flow formation by varying the visible flame shape and
length, depending on the field strength and configuration (Fig.1).
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Fig.1. The electric field effect
on the swirling flame shape and length by varying the bias voltage and
polarity of the electrode. 1. U=0; 2. U=+0.3 kV; 3.
U=+1.8 kV; 4. U=-1.8 kV.
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The
experimental set-up is presented in Fig.2. The experimental
apparatus consists of a gas burner, sectioned water-cooled channel and
central wire electrode. The fuel is injected axially into the burner
through a single-hole nozzle of 20mm inner diameter, while the airflow
- tangentially, through the annular duct using the air swirler with 8
peepholes of 3mm inner diameter. The swirled airflow is supplied
through the radially displaced annular duct up to the burner outlet and
then gradually mixes with the coaxial fuel flow, providing the axial
symmetry of the velocity field. The rate of air injection into the
burner can be varied ranging within 10- 20 l/min, while the propane
rate - from 0.4 to 1 l/min, providing the variation of axial flow rate
in a range of 0,6-1,26 m/s and the variation of the tangential flow
rate in a range of 3,5-7 m/s at nearly constant and relatively high
swirl number of the swirling flow at the burner outlet-
S≈5,6. The
equivalence rate of the air supply in these experiments can be varied
from α=0.7 to α=1.44.
The electric field to the swirling flame flow is applied in a space
between the axially inserted electrode, surface of the burner and
water-cooled channel walls. The bias voltage and polarity of the
axially arranged central electrode in the recent investigations are
varied in the range from –3.0 kV up to +3.0 kV, while the ion current
in the flame in this study is limited to 200 mkA.
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Fig.2. Digital image of the
experimental set-up (a), schematic of the experimental facility (b): 1-
axially arranged central electrode, 2- water-cooled sections of the
channel, 3- peepholes for the diagnostic tools, 4- tangential air
entry, 5-axial propane entry, 6-swirling burner, 7- recirculation zone;
and schematic of the flow field formation (c).
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The investigations of the electric
field effect on the premixed propane/air flame flow include:
- The experimental study of the electric field effect on the
processes of heat and mass transfer;
- The experimental study of the electric field effect on the local
flame composition;
- The experimental study of the electric field effect on the local
temperature and rate of fuel combustion;
- The experimental study of the electric field effect on the levels
of greenhouse emissions (CO2, NOx);
- The experimental study of the electric field effect on the soot
formation, carbon capture and sequestration from the flame flow;
- The experimental study of the electric field effect on
pre-combustion fuel decarbonisation.
Main publications:
- I. Barmina, A. Desnickis, A. Meijere, M. Zake, Active
Electric Control of Emissions From the Swirling Combustion, In: Advanced
Combustion and Aerothermal Technologies: The Biomass and Alternative
Fuels, Ed. Nick Syred, WB/Nato Publishing Unit, P.O.Box 17,3300 AA
Dordrecht, The Netherlands, Springer, 2007, pp. 405-412.
- M. Zaķe, I. Barmina, D. Turlajs, M. Lubāne, A. Krūmiņa.
Swirling Flame. Part 2. Electric Field Effect on the Soot Formation and
Greenhouse Emissions. Magnetohydrodynamics, 2004, Vol. 40, No 2,
p.183-202.
- M. Zaķe, I. Barmina, M. Lubāne. Swirling flame. Part 1.
Experimental Study of the Effect of Stage Combustion on Soot Formation and
Carbon Sequestration from the Nonpremixed Swirling Flame.
Magnetohydrodynamics, 2004, Vol. 40, No 2, p.161-181.
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IPUL at a Glance