Analytical model of high-speed flows has been developed for the channel of quasi-stationary plasma accelerator used to create powerful electric jet plasma engine of new generation. The model of two-dimensional axisymmetric flows is based on the stationary equations of two-fluid magnetohydrodynamics for the ideal plasma and the smoothly varying channel approximation. The new approach to organizing flows using non-equipotential electrodes is associated with the electron current-transport regime, which ensures slipping of the heavy ion component of the plasma along anode and cathode. As a result of studying transonic flows in the profiled channel, the potential distributions along non-equipotential electrodes, as well as the integral characteristics of the flow, including mass flux and thrust, were determined.

Stationary and unstable pulsating flows of ionizing hydrogen in the channel of a quasi-stationary plasma accelerator are considered. Numerical studies of two-dimensional axisymmetric flows are carried out based on the modified magnetogasdynamic (MGD) equations in the approximation of local thermodynamic equilibrium, taking into account electrical conductivity, thermal conductivity, and radiation transport. The generalization of the calculation results led to the formulation of the empirical condition for the stationarity of two-dimensional flows of an ionizing gas.

The purpose of this article is to receive environmental assessments of combustion of different types of coal fuel depending on the preparation (unscreened, size-graded, briquetted and heat-treated) in automated boilers and boilers with manual loading. The assessments were made on the basis of data obtained from experimental methods of coal preparation and calculated methods of determining the amount of pollutant and greenhouse gas emissions, as well as the mass of ash and slag waste. The main pollutants from coal combustion are calculated: particulate matter, benz(a)pyrene, nitrogen oxides, sulfur dioxide, carbon monoxide. Of the greenhouse gases carbon dioxide is calculated. As a result of conducted research it is shown that the simplest preliminary preparation (size-graded) of coal significantly improves combustion efficiency and environmental performance: emissions are reduced by 13% for hard coal and up to 20% for brown coal. The introduction of automated boilers with heat-treated coal in small boiler facilities allows to reduce emissions and ash and slag waste by 2–3 times. The best environmental indicators correspond to heat-treated lignite, which is characterized by the absence of sulfur dioxide emissions.

Model and results of numerical experiments are presented for axisymmetric flows of ionizing gas in the presence of an additional longitudinal magnetic field in the channel of quasi-stationary plasma accelerator considered as perspective electric propulsion plasma engine. A two-dimensional flow model for a three-component medium consisting of atoms, ions, and electrons is based on magnetogasdynamic equations written in terms of the vector potential of magnetic field, taking into account electrical conductivity, thermal conductivity, and radiation transfer. A three-dimensional model of radiative transfer includes main mechanisms of emission and absorption for different parts of the spectrum. Numerical studies of the ionization process and radiation transfer were carried out in an approximation of local thermodynamic equilibrium. The stabilizing effect of flow rotation in the presence of a longitudinal magnetic field and thermal conductivity along the magnetic field on non-stationary unstable flows of ionizing gas, which arise at low discharge currents, is considered.

The purpose of this article is to study experimentally the oxidation process of wood of different degrees of thermal conversion. We compared experimental data of thermogravimetric analysis in the oxidizing environment of raw wood, cellulose, lignin, and wood samples of different degrees of thermal conversion. Thermally treated wood samples were obtained by heating raw pine wood in an inert atmosphere to a given temperature (250, 300, 350, 400, 500 degrees C), followed by rapid quenching in water. All obtained samples were studied by the thermal analysis combined with mass spectrometry (TGA-MS) in inert and oxidizing environments; technical (moisture content, ash content, volatile yield, or W, A, V) and elemental analysis (C, H, O) data were obtained. We propose a new method for kinetic analysis of biomass decomposition: the change in the leading decomposition mechanisms is monitored by the change in the composition of the detected products. Differences between the thermochemical behavior of biomass, its individual components (cellulose and lignin), and their thermal degradation products are discussed.

Injection of plasma flow generated by a quasi-stationary plasma accelerator into a region with a magnetic field created by a series of ring current-carrying conductors forming a solenoid is considered. Numerical studies are carried out based on the set of magnetogasdynamic (MGD) equations represented in terms of the vector potential of the magnetic field, taking into account electrical conductivity, thermal conductivity, and radiation transport, provided that the plasma accelerator and ring conductors are located on the same axis. It is shown that small currents in ring conductors create a magnetic field inside the solenoid, which does not significantly affect the main stream, while simultaneously isolating it from the current coils as a result of the formation of a rarefied plasma layer separating the high-speed flow of dense plasma. Calculations of the MGD problem also show that the plasma flow within the solenoid is not accompanied by an increase in the temperature of the medium.

Fixed-bed combustion of compositions with polymeric materials (for example, municipal solid waste) is often difficult due to the agglomeration phenomenon: when heated, the waste particles swell and emit a significant amount of viscous products, resulting in formation of clumps of particles that have low air permeability. Using experimental and theoretical models, some features of the formation and decomposition of agglomerates are investigated. Samples of the agglomerates were prepared in a laboratory batch unit by heating a mixture of polyethylene granules and clay particles. Using a mathematical model, numerical calculations of the heating regimes were performed under the conditions of an experimental unit. A change in the shape of the agglomerate at different points in time is considered.

New results of the study of high-speed quasi-stationary plasma flows interacting with the magnetic field of ring conductors with different currents is presented. The MHD model uses the vector potential of the magnetic field and takes into account the electrical conductivity, thermal conductivity of the medium, as well as radiation transport. The most optimal mode of transformation of kinetic energy into thermal energy of the plasma during the heating and deceleration of the flow in the magnetic field of ring conductors with the increasing values of currents from one coil to another was determined as a result of numerical calculations within the framework of new approach being developed to solve the problem of the controlled thermonuclear fusion.

Properties of compressible flows in the quasi‐stationary plasma accelerator have been studied in the presence of an additional longitudinal magnetic field and the arising rotation of plasma flow. Numerical study was carried out within the framework of two‐dimensional magnetic hydrodynamics (MHD) model of the axisymmetric plasma flows taking into account the finite conductivity of medium and radiation transport. Dynamics of compressible plasma flows is accompanied by the MHD dynamo effect or generation of magnetic field on a conical shock wave forming at the outlet from the accelerator.

The problems of ecologically clean coal combustion are connected with the need to reduce the formation of pollutants to the environment during thermal transformation of fuel. Currently, about 180-190 million tons of coal are burned in Russia to produce heat and electricity, with more than 60% in the eastern regions of the country. Most of the coal (about 80%) is consumed by large thermal stations, which are equipped with pollutant trapping systems. The remaining part is burned in numerous boiler houses that operate in both urban and rural areas to provide heat to social facilities and the population. The analysis shows that the role of boiler houses increases significantly in the territories with a low population or in remote and decentralized areas. In this regard, the coal pretreatment technology before burning including the thermal preparation of coal is important. The use of thermally prepared fuel (semi-coke) will significantly reduce emissions of NOx and SOx, as well as improve the “culture” of thermal energy production at small boilers by switching to fully automated technologies, as well as significantly reducing the financial burden of utilities by reducing the wage fund and emission fees.

In Russia, significant amounts of waste of logging and woodworking that can be used for energy production are generated. In this paper, we consider an autonomous power supply system, including a wood biomass gasification power plant (BGPP), a diesel power plant (DPP), one or several wind turbines (WT), and electricity consumers with their load schedule. The mathematical formulation of the problem of optimizing the structure and modes of operation of the power supply system is reduced to minimizing the objective function with a number of additional constrains. The objective function is equal to total discounted costs for the construction and operation of the system or the cost of electricity produced. Additional constrains are balances for power, primary, secondary and final energy. The power supply system was modeled for different values of diesel and wood fuels prices, average long-term wind speed, technical and economic indicators of power plants. According to the results of calculations, the zones of technologies efficiency and the cost of electricity produced are determined. It is shown that biomass gasification power plants with gas storage tanks are much more economical than diesel power plants and can displace them at current diesel fuel prices. In areas with high average annual wind speeds, biomass gasification power plants should be used in conjunction with wind turbines.

Abstract Algorithms were developed to solve the problem of radiation transport based on the method of long characteristics, taking into account its optimization in the framework of the quasi-one-dimensional approximation used to study the axisymmetric flows of the ionizing gas in coaxial channels of plasma accelerators. The optimization of calculations of the integral radiation parameters allowed to significantly reduce the calculation time in comparison with three-dimensional model of radiation transport. Calculations of the radiation energy density and the radiation energy flux density, based on various methods, have shown that new algorithms provide high-quality solution of the radiation transport problem.

The article is part of a comprehensive study of the method by synthesis of gas hydrate based on the explosive boiling of liquefied hydrate-forming gas in a volume of water during decompression. Carbon dioxide is used as hydrate-forming gas. This article explores the effect of decompression rates on the amount of gas transferred to a gas hydrate at an initial gas temperature of 2 ° C.

Injection of high-speed plasma flows into a region with a magnetic field created by a current-carrying ring conductor is considered. Analysis is performed on the basis of MHD equations expressed through the vector potential of the magnetic field with allowance for the electric conductivity, thermal conductivity, and radiation transport. The results of numerical experiments demonstrate the possibility of using plasma accelerators as injectors for magnetic confinement devices.

Combustion of solid combustible wastes is the most common way of their disposal. In developed European countries, up to 50% of all municipal waste is burned; in Russia, it is estimated to be less than 2.5%. The efficiency of modern thermal plants operating on MSW and biomass, as well as the capacity of individual combustion units are continuously increasing, approaching the average values that are close to fossil fuels plants. Replacing coal with combustible waste will make it possible to reduce the cost of energy production and reduce the load on waste landfills. However, to this end, it is necessary to solve the problems of organizing efficient combustion as well as cleaning of combustion products. Of particular interest is the co-processing of municipal waste along with lignocellulosic waste from agriculture and the forest industry. In the present work, the thermal behavior of woody biomass and polyethylene mixtures (in different mass ratios) when heated in an oxidizing environment is investigated using methods of thermal analysis. The distribution of the products of pyrolysis and oxidation is investigated by means of mass spectrometry.

ЭКСПЕРИМЕНТАЛЬНОЕ ИССЛЕДОВАНИЕ ИНТЕГРАЛЬНЫХ ХАРАКТЕРИСТИК ПОТОКА ПЛАЗМЫ И РАЗРЯДА КВАЗИСТАЦИОНАРНОГО СИЛЬНОТОЧНОГО ПЛАЗМЕННОГО УСКОРИТЕЛЯ С СОБСТВЕННЫМ МАГНИТНЫМ ПОЛЕМ Н.С.Климов 1 , Д.В.Коваленко 1 , В.Л.Подковыров 1 , Д.М.Кочнев 1 , А.Д.Ярошевская 1 , Р.В.Урлова 1 , А.Н.Козлов 2 , В.С.Коновалов 2 1 АО «ГНЦ РФ ТРИНИТИ», Москва, Троицк, Россия 2 Институт прикладной математики им.М.В.Келдыша Российской академии наук, Москва, Россия Квазистационарные сильноточные плазменные ускорители (КСПУ) активно используются в настоящее время для испытания обращённых к плазме компонентов термоядерного реактора (ТЯР) токамака ИТЭР и исследования эрозии материалов при воздействии концентрированных потоков энергии.В качестве перспективных направлений применения КСПУ рассматриваются также прикладные задачи, связанные с созданием технологий плазменной обработки материалов и разработкой мощных электрореактивных плазменных двигателей.Решение поставленных задач предполагает эксплуатацию КСПУ в новых режимах работы, что, в свою очередь, требует оптимизации плазменного ускорителя с целью обеспечения определённого диапазона параметров плазменного потока, согласования с источником питания, достижения приемлемого КПД, обеспечения устойчивости.В связи с этим актуальными являются экспериментальные исследования взаимосвязи параметров плазменного потока с характеристиками разряда в ускорителе.Эти исследования являются предметом настоящей работы.В режимах работы КСПУ, представляющих интерес для испытания компонентов ТЯР, исследована эффективность передачи энергии потока плазмы на облучаемую твердотельную мишень, а также эффективность преобразования энергии потока плазмы в излучение.При формировании потоков водородной плазмы длительностью 0,5 мс, с энергосодержанием до 150 кДж продемонстрирована возможность обеспечения КПД ускорителя свыше 80%, а КПД преобразования энергии потока в излучение плазмы до 40%.Полученные экспериментальные данные необходимы для развития нового направления исследований, связанного с введением в КСПУ дополнительного продольного магнитного поля в

Abstract Numerical studies of the ionization process are presented for various ways of the gas supplying at the inlet of the coaxial channel of the quasi-stationary plasma accelerator. Simulation of two-dimensional axisymmetric flows of ionizing gas was carried out on the basis of the equations of radiation magnetic gas dynamics taking into account radiation transport. The approximation of local thermodynamic equilibrium in three-component medium consisting of atoms, ions, and electrons was used in the MHD model. It was determined that non-uniform gas inflow at the channel inlet leads to even greater instability of the pulsating unsteady flows of the ionizing gas in the plasma accelerator. The method of long characteristics was used in the 3D model of radiation transport, including the basic mechanisms of emission and absorption for different portions of the spectrum. The radiation field in the ionizing gas flow was determined, including the integral radiation characteristics and the spectral radiation intensities in the narrow ranges of frequencies or photon energies.

Abstract The use of biomass in the energy sector is associated with two important tasks: reducing the dependence of energy systems on expensive high-quality fuel, and increasing the environmental efficiency of thermal power plants (by processing carbon-containing waste and, in some cases, reducing harmful emissions). In addition to co-combusiton, other methods of fuels co-processing are possible, including co-gasification. The process of gasification of low-grade fuels can be unstable because of their low calorific value, often accompanied by the formation of tar products, so the addition of coal improves the efficiency of co-conversion. On the other hand, the high reactivity of biomass can contribute to the stabilization of combustion and gasification regimes of fuels with low-reactivity, such as coals with high degree of metamorphism or petcoke. In this paper, the process of pulverized fuel gasification is considered, and limitations on the efficiency associated with the melting of ash are investigated.

Numerical study of the interaction of high-velocity flow generated by the quasi-stationary plasma accelerator with magnetic field created by the set of ring conductors with a current is presented. Simulation was carried out on the basis of the set of the MHD equations taking into account the electrical conductivity, thermal conductivity, and radiation transport. Possibility of a step-by-step increase in plasma temperature is revealed as a result of flow deceleration in magnetic field of several coils with a current.