Effect of a gas-vortex stabilization method on the kinematic properties of the jet in metal-cutting plasmatrons

Various methods of gas-vortex stabilization in plasma cutting torches are investigated. The results of the study demonstrate the dependence of the angle of gas injection into the nozzle on the kinematic and kinetic characteristics of plasma jet and, consequently, on the cutting parameters. Increased radial velocity component at the swirler output provides better uniformity of the velocity distribution and kinetic properties of the jet in the affected zone of a cut metal. As a conclusion, it is recommended to use the suggested narrow-jet-plasma technology for cutting thin sheet metals. © 2019 IOP Publishing Ltd

Temperature influence on the effectiveness of gas-vortex stabilization in plasma torches

The results of the efficiency studies of gas-vortex stabilization systems for metal-cutting plasmatrons are presented. It is noted that the method of efficiency evaluation developed by the authors should be based on the calculation of the uniformity of the gas flow velocity distribution over the section of the gas-heating path of the plasma torch. Various simplified and accurate estimation methods are proposed. The results of calculation of the velocity distribution in the control section for different modifications of plasma torches are presented. Calculations are made on the "cold" model gas flow and its heating by a plasma arc. It is shown that when heated by a plasma arc, the flow rate at the inlet to the nozzle channel of the plasma torch and the degree of irregularity of the velocity distribution in the control section increase. By methods of statistical analysis the main parameter of the effectiveness evaluation of individual gaseous-vortex stabilization was chosen - criterion of the velocity variations. Demonstrated the advantages of the new upgraded torches, including working on technology narrow jet plasma, from the point of view of the effectiveness of gas-vortex stabilization. © Published under licence by IOP Publishing Ltd

Temperature influence on the effectiveness of gas-vortex stabilization in plasma torches

The results of the efficiency studies of gas-vortex stabilization systems for metal-cutting plasmatrons are presented. It is noted that the method of efficiency evaluation developed by the authors should be based on the calculation of the uniformity of the gas flow velocity distribution over the section of the gas-heating path of the plasma torch. Various simplified and accurate estimation methods are proposed. The results of calculation of the velocity distribution in the control section for different modifications of plasma torches are presented. Calculations are made on the "cold" model gas flow and its heating by a plasma arc. It is shown that when heated by a plasma arc, the flow rate at the inlet to the nozzle channel of the plasma torch and the degree of irregularity of the velocity distribution in the control section increase. By methods of statistical analysis the main parameter of the effectiveness evaluation of individual gaseous-vortex stabilization was chosen - criterion of the velocity variations. Demonstrated the advantages of the new upgraded torches, including working on technology narrow jet plasma, from the point of view of the effectiveness of gas-vortex stabilization. © Published under licence by IOP Publishing Ltd

Influence of plasma torch design on cutting quality during precision air-plasma cutting of metal

Optical interferometry and metallographic analysis were used to study the structure of cutting seams obtained after 09G2S steel cutting by a PMVR-5 plasma torch. These plasma torches have many design features in the gas-dynamic stabilization system of the plasma arc. The application of a new plasma torch can obtain higher quality and lower energy costs of cutting medium-thick 09G2S steel. Metallographic analysis has shown that the qualitative composition of the cut surface structure is almost the same, so priority criteria for comparative quality analysis are surface microgeometry parameters. The parameter evaluation shows high quality of cutting almost along the entire length of a cut, since the technological feature influence of plasma arc cut into the metal affects less than 0.3 mm from the sheet edge. The use of additional methods of gas-dynamic stabilization in PMVR-5.2 plasma torch (feed symmetry with a double swirl system of plasma-forming gas) makes it possible to achieve additional advantages in terms of surface quality compared to PMVR-5.1. A number of features that affects cut quality when cutting metals of different thicknesses for welding depends on the inclination angle of a plasma torch during cutting. Estimates of the surface layer hardness indicate minimal deviations from the requirements of GAZPROM Standard 2-2.4-083 (instructions on welding technologies in the construction and repair of field and main gas pipelines), which allows further use of cutting seams obtained by studied plasma torches for welding without removing thermal influence zones. Thus, the application of new plasma torches for precision-finishing plasma cutting of metals, including production of welded joints, is possible. © 2020, Allerton Press, Inc

Effect of a gas-vortex stabilization method on the kinematic properties of the jet in metal-cutting plasmatrons

Various methods of gas-vortex stabilization in plasma cutting torches are investigated. The results of the study demonstrate the dependence of the angle of gas injection into the nozzle on the kinematic and kinetic characteristics of plasma jet and, consequently, on the cutting parameters. Increased radial velocity component at the swirler output provides better uniformity of the velocity distribution and kinetic properties of the jet in the affected zone of a cut metal. As a conclusion, it is recommended to use the suggested narrow-jet-plasma technology for cutting thin sheet metals. © 2019 IOP Publishing Ltd.Ministry of Science and Higher Education of the Russian Federation: 13.10317.2018/11.12The work was executed under the support of state assignment of the Ministry of Science and Higher Education of the Russian Federation No. 13.10317.2018/11.12

HIGH-PERFORMANCE SIMULATIONS OF POPULATION-GENETIC PROCESSES IN BACTERIAL COMMUNITIES USING THE HAPLOID EVOLUTIONARY CONSTRUCTOR SOFTWARE

Three high-performance versions of the Haploid Evolutionary Constructor program are presented (http://evol-constructor.bionet.nsc.ru). The software was designed for simulating the functioning and evolution of microbial communities. These high-performance versions are to be run on systems with shared and distributed memory, using CPU and/or GPU. Almost linear acceleration has been achieved on clusters and multi-core CPU. On GPU systems, the simulation time was reduced to several minutes (dozens of hours on CPU)

Phylostratigraphic analysis of gene networks of human diseases

Phylostratigraphic analysis is an approach to the study of gene evolution that makes it possible to determine the time of the origin of genes by analyzing their orthologous groups. The age of a gene belonging to an orthologous group is def ined as the age of the most recent ancestor of all species represented in that group. Such an analysis can reveal important stages in the evolution of both the organism as a whole and groups of functionally related genes, in particular gene networks. In addition to investigating the time of origin of a gene, the level of its genetic variability and what type of selection the gene is subject to in relation to the most closely related organisms is studied. Using the Orthoscape application, gene networks from the KEGG Pathway, Human Diseases database describing various human diseases were analyzed. It was shown that the majority of genes described in gene networks are under stabilizing selection and a high reliable correlation was found between the time of gene origin and the level of genetic variability: the younger the gene, the higher the level of its variability is. It was also shown that among the gene networks analyzed, the highest proportion of evolutionarily young genes was found in the networks associated with diseases of the immune system (65 %), and the highest proportion of evolutionarily ancient genes was found in the networks responsible for the formation of human dependence on substances that cause addiction to chemical compounds (88 %); gene networks responsible for the development of infectious diseases caused by parasites are signif icantly enriched for evolutionarily young genes, and gene networks responsible for the development of specif ic types of cancer are signif icantly enriched for evolutionarily ancient genes

Development of Equipment and Technology for Precision Air-Plasma Cutting of Plate Steel

Abstract: This work studies the structure of cutting seams obtained after cutting steel 09G2S with a new PMVR-5.3 narrow-jet plasma torch which has a number of design features in the gas dynamic stabilization system (GDS) of plasma arc. To increase the efficiency of the GDS in the PMVR-5.3 plasma torch, a symmetrical input of plasma-forming gas (PFG) into the flow division system and a gas-dynamic flow stabilizer using two (forming and stabilizing) swirlers with a variable number of swirl channels were used. It is shown that the achieved advantage in the GDS efficiency makes it possible to obtain a high cutting quality on steel 09G2S with a thickness of 40 mm at high productivity and lower energy costs. Analytical methods have proven a high precision degree of cutting with the new torch—a small cut width, no melting and rounding of the upper edge, as well as a grate in the lower part of the cut and splashes in its upper part, almost zero angular deviation, minimal surface microtopography values and width of the thermal impact zone. A metallographic analysis and a hardness measurement detected three subzones in the thermal impact zone with significant structural changes in two of them. Several factors are noted influencing the revealed structuring changes as well as the changes in the elemental composition of the cutting seam surface layer revealed during the X-ray spectral analysis. Attention is drawn to the surface microtopography after plasma cutting. This topography is commensurate by all quality indicators with the postmilling machining of the surface and corresponds to the second class of surface cleanliness. It is proven that the new narrow-jet plasma torch allows performing a high-quality cutting of plate steel with thicknesses up to 40 mm or more. However, the welding of blanks without pre-machining can be carried out at a cut thickness of no more than 20 mm. © 2022, Allerton Press, Inc

On the Efficiency of Nitrogen-Containing Gaseous Waste Plasma Afterburning

The paper is devoted to the study of the plasma neutralization technology for toxic waste in the gaseous phase. It is noted that for effective implementation of plasma processes in waste processing technologies, it is necessary to search the optimal solutions taking into account the criteria of quality, productivity, cost and safety. In order to determine the feasibility of using plasma incineration technology, attention is paid to the definition of the appropriate nomenclature for gaseous toxic waste. The technology of plasma neutralization for thermal waste processing products - superoxicants (dioxins) and nitrogen-containing gas emissions (ammonia and nitrogen oxides) is studied. A modernized design of the plasma torch for the gaseous waste utilization is proposed. The known methods of thermal destruction for ammonia and nitrogen oxides are considered. Temperature approximations of their decomposition duration and efficiency in the range of plasma heating temperatures are found. The gas-dynamic parameters of the air-plasma flow in the process of nitrogen-containing gases thermal heating by plasma jet are determined using machine modelling methods. The effectiveness of the considered plasma neutralization technology is proved. The results of these studies should allow us to further formulate commonly used in engineering practice principles and methods for designing high-performance plasma heating technology. © Published under licence by IOP Publishing Ltd.The work is executed at support of RFBR grant 19-08-00190

NUMERICAL SIMULATION OF PHYSICAL PROCESSES FOR SOLVING PROBLEMS OF ENVIRONMENTAL ENGINEERING BY PLASMA METHODS

The advantages of technologies based on high-temperature plasma action on materials are considered. The parameters of the gas flow in the plasma torch mixing chamber for environmental technologies are determined by numerical modeling methods. The directions of further research and development necessary for the creation of plasma neutralization technology with maximum efficiency are outlined.Рассмотрены достоинства технологий, основанных на высокотемпературном плазменном воздействии на материалы. Методами численного моделирования определены параметры газового потока в камере смешения плазмотрона для экологических технологий. Обозначены направления дальнейших исследований и разработок, необходимых для создания максимально эффективной технологии плазменного обезвреживания