Fire in enclosed military environments such as ship holds, aircraft cockpits and ground vehicles is a major cause of material destruction and jeopardizes the lives of warfighters. For example, a shipboard fire on the aircraft carrier USS George Washington in May 2008 burned for 12 hours and caused an estimated $70 million in damage.
For nearly 50 years, despite the severity of the threat from fire, no new methods for extinguishing or manipulating fire were developed. In 2008, DARPA launched the Instant Fire Suppression (IFS) program to develop a fundamental understanding of fire with the aim of transforming approaches to firefighting.Traditional fire-suppression technologies focus largely on disrupting the chemical reactions involved in combustion. However, from a physics perspective, flames are cold plasmas. DARPA theorized that by using physics techniques rather than combustion chemistry, it might be possible to manipulate and extinguish flames. To achieve this, new research was required to understand and quantify the interaction of electromagnetic and acoustic waves with the plasma in a flame.
One of the technologies explored was a novel flame-suppression system that used a handheld electrode to suppress small methane gas and liquid fuel fires. In the video below, performers sweep the electrode over the ignited burner array and progressively extinguish the 10-cm2 gas flame. Since the electrode is sheathed in ceramic glass, no current is established between the electrode and its surroundings. A visualization of gas flows during the suppression would show that the oscillating field induces a rapid series of jets that displace the combustion zone from the fuel source, leading to extinguishment of the fire. Put simply, the electric field creates an ionic wind that blows out the flame. This same approach was not able to suppress a small heptane pool flame.
Performers also evaluated the use of acoustic fields to suppress flames. In the video below, a flame is extinguished by an acoustic field generated by speakers on either side of the pool of fuel. Two dynamics are at play in this approach. First, the acoustic field increases the air velocity. As the velocity goes up, the flame boundary layer, where combustion occurs, thins, making it easier to disrupt the flame. Second, by disturbing the pool surface, the acoustic field leads to higher fuel vaporization, which widens the flame, but also drops the overall flame temperature. Combustion is disrupted as the same amount of heat is spread over a larger area. Essentially, in this demonstration the performers used speakers to blast sound at specific frequencies that extinguish the flame.IFS Phase II was completed in December 2011. IFS performers succeeded in demonstrating the ability to suppress, extinguish and manipulate small flames locally using electric and acoustic suppression techniques. However, it was not clear from the research how to effectively scale these approaches to the levels required for defense applications.
DARPA Public Affairs | EurekAlert!
New Boost for ToCoTronics
23.05.2019 | Julius-Maximilians-Universität Würzburg
The geometry of an electron determined for the first time
23.05.2019 | Universität Basel
Physicists at the University of Basel are able to show for the first time how a single electron looks in an artificial atom. A newly developed method enables them to show the probability of an electron being present in a space. This allows improved control of electron spins, which could serve as the smallest information unit in a future quantum computer. The experiments were published in Physical Review Letters and the related theory in Physical Review B.
The spin of an electron is a promising candidate for use as the smallest information unit (qubit) of a quantum computer. Controlling and switching this spin or...
Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...
With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.
Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...
'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.
However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...
Working group led by physicist Professor Ulrich Nowak at the University of Konstanz, in collaboration with a team of physicists from Johannes Gutenberg University Mainz, demonstrates how skyrmions can be used for the computer concepts of the future
When it comes to performing a calculation destined to arrive at an exact result, humans are hopelessly inferior to the computer. In other areas, humans are...
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