The Formation of a Flame Front in a Hydrogen–Air Mixture during Spark Ignition in a Semi-Open Channel with a Porous Coating

An experimental study of ignition and flame front propagation during spark initiation in a hydrogen–air mixture in a semi-open channel with a porous coating is reported. The bottom surface of the channel was covered with a porous layer made of porous polyurethane or steel wool. The measurements were...

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Bibliographic Details
Published in:Fire (Basel, Switzerland) Switzerland), 2023-12, Vol.6 (12), p.453
Main Authors: Golovastov, Sergey, Bivol, Grigory, Kuleshov, Fyodor, Golub, Victor
Format: Article
Language:English
Subjects:
Acoustics
Coating effects
Coatings
Deflagration
Disturbances
Equivalence ratio
Experiments
flame front
Flame propagation
Geometry
High speed cameras
Hydrogen
Mixtures
Open channels
Polyurethane
Polyurethane resins
Pore size
porous layer
Porous materials
Propagation
Recording equipment
Spark ignition
Stability analysis
steel wool
Synthesis gas
Velocity
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Summary:An experimental study of ignition and flame front propagation during spark initiation in a hydrogen–air mixture in a semi-open channel with a porous coating is reported. The bottom surface of the channel was covered with a porous layer made of porous polyurethane or steel wool. The measurements were carried out for a stoichiometric mixture (equivalence ratio ER = 1.0) and for a lean mixture (ER = 0.4) of hydrogen with air, where ER is the molar excess of hydrogen. The flame front was recorded with a high-speed camera using the shadow method. Depending on the pore size, the velocity of the flame front and the sizes of disturbances generated on the surface of the flame front were determined. Qualitative features of the deflagration flame front at ER = 0.4, consisting of disturbances resembling small balls of flame, were discovered. The sizes of these disturbances significantly exceed the analytical values for the Darrieus–Landau instability. The effect of coatings made of porous polyurethane or steel wool is compared with the results obtained for an empty smooth channel. Depending on the hydrogen concentration in the hydrogen–air mixture, the velocity of the flame front compared to a smooth channel was three times higher when the channel was covered with steel wool and five times higher when the channel was covered with porous polyurethane.
ISSN:2571-6255
2571-6255
DOI:10.3390/fire6120453