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What is gas detonation? First of all, it is an explosion, often fierce and destructive. The heart of this process is a high-speed (supersonic) combustion of gas fuel (acetylene, propane, butane, etc.) forming a powerful shock wave in which energy of chemical conversion transforms into thermal and kinetic energy (temperature--up to 4,000 °C, flow rateover 1 km/sec). The main task here is to tame the "fiery beast" and make it work for the benefit of people.
This problem has been studied in the RAS SB Institute of Hydrodynamics named after M. Lavrentyev (Novosibirsk) over 50 years. As early as in the 1960s, Bogdan Voitsekhovsky (Academician from 1991), Vladislav Mitrofanov, and Marlen Topchiyan (future doctors of sciences in physics and mathematics) discovered cellular structure of detonation front and spin detonation that were later registered as discoveries, and a series of studies carried out in conjunction with colleagues from Moscow was awarded the Lenin Prize, the highest national award of that time. Later on, the fundamental
Vladimir Ulyanitsky, Head of the Laboratory of Detonation Flows of the RAS SB Institute of Hydrodynamics, and research engineer Alexander Kovalenko.
results of studies were actively transformed by employees of the Institute who proposed technical solutions and new industrial technologies. They became a topic of the interview given by Vladimir Ulyanitsky, Dr. Sc. (Tech.), Head of the Laboratory of Detonation Flows of the RAS SB Institute of Hydrodynamics, to the correspondent of the Science in Siberia newspaper Yulia Alexandrova.
According to the scientist, one of the applications of gas detonation is detonation spraying when explosion energy is used to form protective coverings on the surface of components of different design and purpose. The particles of powdered material are heated up by explosion products to melting point and gather bullet speed. When colliding with the processed detail, they firmly stick to its surface forming a layer of compact covering. To realize this process in practice, special equipment is required. The first generation of such devices was designed in our country in the 1970s, but, as a rule, they were developed by engineers who were not specialists in explosion physics, which affected stability of the process and quality of coverings.
In the early 1980s, the USSR Ministry of Aircraft Industry proposed the Institute of Hydrodynamics to focus on these problems and improve the equipment that was already widely used to produce aircraft engines. After this task was successfully completed, a team of young specialists led by Tamara Gavrilenko and Yuri Nikolayev, Cands Sc. (Phys. & Math.), decided to take up a challenge and design a totally new apparatus. In two years, they presented a detonation gun "Ob" that differed fundamentally from its predecessors by process stability, high quality of received coverings and new technological potentialities. Approximately ten national and foreign patents prove unique nature of the proposed solutions. The first sample of this device was put into operation in the late 1980s at the aircraft engine building plant in Ufa; concurrently, its industrial production was launched at Berdsk electromechanical plant in the Novosibirsk Region. Unfortunately, in the 1990s, the production was terminated. The Laboratory was forced to switch to new tasks not typical of the subsivisions of the Academy of Sciences in favorable conditions--we mean studies aimed to find ways of application of advanced technology for public consumption. Scientists proved that technology of strengthening main parts used in aircraft engineering could be successfully applied to repair all types of components and spare parts for cars, locomotives, machines, other types of equipment and even to renew complex joints, for example, internal-combustion engine cylinder blocks, compressors of refrigerating plants, etc.
The Laboratory not only demonstrated fundamental options of the technology under consideration, but proposed a complete technological cycle. Eventually, all production equipment is successfully put into operation and used at small motor repair plants and works in Siberia, Kirgizia, Uzbekistan, and even in Moscow.
Great demand for the technology is explained by its high economic efficiency. For example, less than a kilo of a powdered material can renew a multikilogram crankshaft of a truck or a bulldozer. Moreover, the renewed component becomes, after increasing its wear resistance, even better than a new one.
In the late 1990s, the Laboratory was proposed to challenge another technological task. OAO Galogen (Perm), one of the major national producers of chemicals, addressed local specialists to consider the idea of metallization of fluoroplastic products. This plastic characterized by unique useful properties has one unpleasant technical "defect": it is impossible to stick it by any means, which limits its application options. Detonation spraying successfully solved this problem, even though the proposed approach initially seemed incredible. Is it really possible to cover plastic with metal by way of explosion? Fertile imagination! But it turned out that "delicate" gas detonation can introduce half-fused particles of aluminum into polymer without damaging it and then form a solid metal covering that can be glued to any surface.
The scientists patented their idea and then took it to its commercial use: the first specialized apparatus capable of covering fluoroplastic with metal was put into operation in Perm in 2005. It became a prototype of detonation spraying devices of a new generation. Creation of multifunctional instruments was very expensive, and national industry could not afford it yet. Fortu-
nately, the technology got into a focus of close attention of the National Engineering School in Saint-Etienne (France). Starting from the 1980s, Prof. Igor Smurov has been working in this field and established a Russian-language laboratory there. By the way, he was granted a megagrant and today he is realizing it at the Moscow State Technological University Stankin, which means that the technology developed by Novosibirsk scientists is being promoted in Moscow by the professor from France.
The first multifunctional computer complex of a new generation was sent to France in the summer of 2007. In fact, it was the first special-purpose detonation spraying robot able to process components of irregular shape. Engineering solutions used in this device are protected by three Russian patents.
The working up of the commercial product of value was financed by the company Siberian Technologies of Protective Coverings, which is now producing these units at the technology park of the Novosibirsk Science Center. The company also attracts customers and sells the equipment. Moreover, employees of the RAS SB Institute of Hydrodynamics take part in the improvement of technologies, including adjustment of equipment and training of specialists.
The company was one of the partners to improve the design solution of the CCDS2000 unit (Computer Controlled Detonation Spraying), which was brought to the level of world export standards. This expanded export geography. The consumers are both large research centers and industrial enterprises, such as aircraft and machine-building plants in China. The work arose interest in Russia too: strengthening and protective coverings for modern drilling and oil production, oil and gas transportation equipment are made using detonation spraying technology. The resources of the above-mentioned computer complex of a new generation were actively used to expand options of the detonation spraying equipment.
The new technology is actively used in other industries too. For example, a high voltage ceramic insulation of electrophysical units operating in a highly radioactive environment -- the technology was used to improve high current transformers manufactured by the Novosibirsk Institute of Nuclear Physics named after G. Budker for the Fermi National Accelerator Laboratory (USA). Together with the Institute of Catalysis named after G. Boreskov, scientists of the RAS SB Institute of Hydrodynamics developed reactors for high-temperature conversion of gasoline-air mixture into synthesis gas where the detonation covering is used as a catalyst carrier. The Laboratory led by Vladimir Ulyanitsky in conjunction with the Institute of Chemistry of Solids is developing new composite nanostructural materials characterized, inter alia, by high antibacterial properties of nanoparticles of silver produced during formation of a composite using detonation spraying technology.
There are many joint projects implemented in association with other RAS SB institutions, in particular, with the Institute of Inorganic Chemistry named after A. Nikolayev and the Institute of Theoretical and Applied Mechanics named after S. Khristianovich, Tomsk and Krasnoyarsk laboratories. Detonation coverings invented originally for nuclear industry are also used in power plants. In collaboration with the French colleagues, scientists from Novosibirsk proved efficiency of detonation spraying technology for the ITER project--the first in the world thermonuclear reactor being built near Marcel. The national aircraft industry is not forgotten either. Modern detonation spraying equipment makes it possible to produce coverings for aircraft components, wear resistance of which is many times higher than that achieved traditionally. The first devices of a new generation designed at the RAS SB Institute of Hydrodynamics will soon be sent to OAO Kuznetsov (Samara) and Ufa Motor-Building Production Enterprise.
Yu. Alexandrova, Gas Detonation Innovations.-- "Science in Siberia" newspaper. No. 47, 2013
Illustrations supplied by Vladimir Ilyanitsky and Vladimir Novikov