When hydrogen is burned, the flame can spread in a very narrow space, forming a fractal pattern. The discovery made by Spanish and German researchers can help improve the safety of generators using this fuel.
This Hydrogen flame They can even spread in surprisingly narrow spaces with almost no fuel, and spread to form eye-catching fractal structures.
This is the unexpected physical behavior of this gas when it burns, detected by a scientific team led by researchers from Europe. Carlos III University of Madrid (UC3M).The results are published in the journal Medical letterIt can be used to improve the safety of hydrogen-based power generation equipment.
Experiments conducted in the combustion chamber have shown that hydrogen flames can survive under more extreme conditions than previously thought.
“Our article shows that hydrogen flames can spread in very narrow spaces (such as narrow spaces). One millimeter, Causing undesirable dangerous situations”, he explained Fernando Vega, Is one of the UC3M researchers who completed most of the experimental work.
Using hydrogen as a fuel can help reduce carbon dioxide emissions, but there are certain risks in its storage and transportation. This work proves with empirical evidence that gas will burn in unexpected situations.
To this end, the research team tested the gaseous fuel diluent in a space several millimeters wide and found that even if the concentration of hydrogen is only 5%, hydrogen can burn stably.
High-speed camera can be used to view fractals
The hydrogen flame is Almost invisible There is very little radiation visible to the naked eye, so it is difficult to detect. In order to achieve this goal, the researchers used a special method to track its movement, and used a high-speed camera to track the trajectory followed by the flame spreading.
Therefore, they verified that they produce fractals when they are extended, that is, the basic structure of the geometric shapes they adopt is repeated in different proportions. Another UC3M co-author pointed out: “The video recording reveals this fractal structure, which precisely allows for the efficient acquisition of new fuel during combustion.” Mario Sanchez Sanz.
Eduardo Fernández-Tarrazo from the thermal and fluid engineering department of the university also participated in the work, and Daniel Martínez Ruiz from the university also participated in the work. Madrid University of Technology (UPM), Mike Kuznetsov del Karlsruhe Institute of Technology (Germany) and Joaquim Grune from the group Pro-Science GmbH (Germany).
The author recalled that hydrogen is configured as a clean and efficient energy source, so hydrogen-based power generation technology will significantly increase its use in the near future. He warned: “The design of these technologies and security protocols must consider these new propagation mechanisms.” Martinez RuizProfessor of ETSI School of Aeronautics and Astronautics at UPM (ETM).
The results of this study may be useful to engineering teams designing hydrogen storage systems, who need to consider their extremely high flammability even in very confined spaces.
This Hydrogen fuel cell For example, they are used as energy sources for cars and motorcycles. Sánchez Sanz (Sánchez Sanz) said: “The escape of hydrogen and its accumulation in a confined environment can cause this type of flame.”
Researchers believe that more such studies are needed to assess the safety related to the leakage of hydrogen-powered vehicles and other related equipment. Especially in the current context, when faced with the need to reduce and fight against greenhouse gas emissions, climate change, It seems necessary to accelerate the development and use of hydrogen-based power generation technology.
F.Veiga-López and others. “Unexpected propagation of ultra-dilute hydrogen flame in a narrow gap”. Physical Wright Pastor 124, 174501, 2020