Whitesides Research

Techniques: Flames

Real time video of the extinction of a methane/air non-premixed flame by an AC inhomogeneous electric field.

This video (real time) shows the effect of an oscillating electric field on a methane flame burning in air (the flame is ~15 cm tall in this case).
The field is applied via a wire electrode (shown on the left of the flame, pointed at the base of the flame), which is insulated by a glass shell, raised to a large oscillating potential.
The counterelectrode is outside the field of view and consists of a 50x50cm vertically oriented grounded plate.
The field conditions here have been chosen to show effective suppression in ~100 ms. 

Last updated on December 1, 2011

Extinction of a methane/air non-premixed flame by an AC inhomogeneous electric field

This video (three loops, the first two loops are in real time, the third loops is half speed) shows the effect of an oscillating electric field on a methane flame burning in air (the flame is ~50 cm tall in this case).
The field is applied via a wire electrode (shown on the left of the flame, pointed at the base of the flame), which is insulated by a glass shell, raised to a large oscillating potential.
The counterelectrode is on the right side of the box containing the flame and consists of a 50x50cm vertically oriented grounded plate.
The field conditions here have been chosen to show effective suppression in ~300 ms. 

Last updated on December 1, 2011

Slow motion video of the extinction of a methane/air non-premixed flame by an AC inhomogeneous electric field.

This video (slow motion) shows the effect of an oscillating electric field on a methane flame burning in air (the flame is ~15 cm tall in this case).
The field is applied via a wire electrode (shown on the left of the flame, pointed at the base of the flame), which is insulated by a glass shell, raised to a large oscillating potential.
The counterelectrode is outside the field of view and consists of a 50x50cm vertically oriented grounded plate.
The field conditions here have been chosen to show effective suppression in ~50 ms. 

Last updated on December 1, 2011

Effect of field strength on the interaction of a methane/air non-premixed flame with an AC inhomogeneous electric field.

This video (real time) shows the effect of an oscillating electric field of varying intensity and constant frequency on a methane flame burning in air (the flame is ~15 cm tall in this case).
The field is applied via a wire electrode (shown on the left of the flame, pointed at the base of the flame), which is insulated by a glass shell, raised to a large oscillating potential.
The counterelectrode is outside the field of view and consists of a 50x50cm vertically oriented grounded plate.
The field conditions here have been chosen to show the field-dependent transition between attractive interaction and repulsive interaction.

Last updated on December 1, 2011

Effect of frequency on the interaction of a methane/air non-premixed flame with an AC inhomogeneous electric field.

This video (real time) shows the effect of an oscillating electric field of constant intensity and increasing frequency on a methane flame burning in air (the flame is ~15 cm tall in this case).
The field is applied via a wire electrode (shown on the left of the flame, pointed at the base of the flame), which is insulated by a glass shell, raised to a large oscillating potential.
The counterelectrode is outside the field of view and consists of a 50x50cm vertically oriented grounded plate.
The field conditions here have been chosen to show the increase of repulsion with frequency.

Last updated on December 1, 2011

Repulsion of a methane/air non-premixed flame by a AC inhomogeneous electric field.

This video shows the effect of an oscillating electric field on a methane flame burning in air (the flame is ~15 cm tall in this case).
The field is applied via a wire electrode (shown on the left of the flame, pointed at the base of the flame), which is insulated by a glass shell, raised to a large oscillating potential.
The counterelectrode is outside the field of view and consists of a 50x50cm vertically oriented grounded plate.
The field conditions here have been chosen to show a level of repulsion just below the suppression threshold.

Last updated on December 1, 2011

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