Flame
& Corona Interaction Testing
American
Antigravity's coronal flame-testing includes a series of
experiments to determine if the flame of a common-candle
might interact with the charged air-gap present between
the Lifter's emitter and collector wires during operation.
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Flame-Test
Video
Watch
the flame-testing mpeg video clip from the AAG video archives!
Video
Archive
Experimental
Setup
The
corona flame-test experiment was designed so that a vertically
oriented flame would rise and pass through the horizontally
oriented air-gap in the Lifter.
The
Lifter was mounted sideways on top of the candle using 1/8"
risers between the Lifter and the top of the candle.
The
GRA Power-Supply was utilized to create the high-voltage
corona between the emitter and collector wires, with an
operating voltage of approximately 30kV.
The
distance between the emitter and the collector was approximately
5cm in width. The candle flame varied in length between
1cm and 4 cm in height, depending mostly on airborne-agitation
from higher thrust and voltage levels.
Flame
Plasma
The
flame interacts with the corona between the emitter and
collector because the flame contains a conductive plasma.
Common flames can contain ionization rates of approximately
10% or more, in which the hot-exhaust gases contain free
electrons in addition to atoms with a net-charge from which
they have been stripped. The electrically-charged nature
of these particles makes them conductive, which interacts
with the electrically-charged corona in the air-gap.
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Experimental Results
The
flame-test experiment demonstrated some very interesting
interactions between the flame and the corona air-gap of
the Lifter during operation. As seen in the topmost photo
above, no interaction occurred while the high-voltage power-supply
remained off. The topmost photo above serves as a baseline-photo
to help the reader establish what an unaffected flame looks
like.
As shown in the second photo from the top, entitled "Flame
Bisecting Air-Gap", when high-voltage power is applied
across the air-gap from the emitter (left) to the collector
(right), the flame immediately interacts with the corona
flowing across the air-gap. In the second photo, the flame
can be clearly seen looping back over on itself to intersect
with the collector wire.
The flame is drawn towards the collector when power is applied
partially through an aerodynamic push from ions travelling
from the emitter to the collector, but also because the
flame is a mixture of combustion-gasses and gas-plasma that
picks up and carries charges in the air-gap to the collector.
In essence, the flame serves as a charge-transport mechanism
across the air-gap, and as such it picks up ions from the
surrounding air in the corona and delivers them to the collector.
The third and fourth photos show very long arcing between
the emitter, the flame, and the collector. The arcs occurred
periodically at intervals of approximately 1 to 2 seconds
between them, and the majority of arcing occurred between
the flame and the collector-wire.
The arcs between the emitter, flame, and collector were
surprisingly long. While arcs are not uncommon at high-voltages,
the spark-lengths of up to 5cm occurred at very low settings
on the power-supply. Additionally, arcing only began to
occur when the flame was lit -- no arcing happened after
the flame was extinguished during the test.
The coronal arcing also demonstrated the unique quality
of not resetting the GRA power-supply circuitry, which typically
happens as part of the built-in overvoltage-protection for
the GRA power-supply. The author believes that this is because
the arcing facilitated rapid charge transfer, but not in
large-volumes as would a normal arc in an operating Lifter.
It may also be that arcing was limited to the number of
ions in the flame's plasma, which would be a limiting factor
as to the volume of current that could be delivered in each
arcing event.
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