Papers by Aleksey Bocharov
39th Aerospace Sciences Meeting and Exhibit, 2001
45th AIAA Aerospace Sciences Meeting and Exhibit, 2007
33rd Plasmadynamics and Lasers Conference, 2002
38th Plasmadynamics and Lasers Conference, 2007
39th Aerospace Sciences Meeting and Exhibit, 2001
39th Plasmadynamics and Lasers Conference, 2008
28th Plasmadynamics and Lasers Conference, 1997
A new analytical-numerical theory of contraction phenomena on electrode covered by non-linear res... more A new analytical-numerical theory of contraction phenomena on electrode covered by non-linear resistive layer in low-temperature plasma flow is developed. A numerical studies of a 3D discharge on a flat electrode is carried out. The influence of magnetic field on the structure of an arc discharge is investigated.
Technical Physics Letters, 2011
ABSTRACT
45th AIAA Aerospace Sciences Meeting and Exhibit, 2007
Fluid Dynamics, 1986
In this paper an approach to the solution of problems of matched heat transfer at inhomogeneous w... more In this paper an approach to the solution of problems of matched heat transfer at inhomogeneous walls is formulated. Special attention is paid to the longitudinal heat flow effect in the inhomogeneous wall thickness and in the flow of liquid or gas bathing the wall. Much high-temperature gas-dynamic apparatus uses walls with thermophysical properties that are highly nonuniform in the direction of flow. "Composite" walls of this kind with alternating metal and ceramic elements (Fig. I) are used, in particular, in the channels of ~HD generators where, moreover, the nonuniformity of the electrophysical properties of the structural materials of the walls is also important. In practical problems the heat transfer at such walls is usually calculated in the boundary layer approximation. However, the applicability of the thermal boundary layer approximation to composite walls requires a special analysis, associated, for example, with the need to estimate the effect of the longitudinal heat flows along the wall and in the flow in regions with high longitudinal temperature gradients.
Materials, 2020
Synthesis of graphene materials in a plasma stream from an up to 40 kW direct current (DC) plasma... more Synthesis of graphene materials in a plasma stream from an up to 40 kW direct current (DC) plasma torch is investigated. These materials are created by means of the conversion of hydrocarbons under the pressure 350–710 Torr without using catalysts, without additional processes of inter-substrate transfer and the elimination of impurities. Helium and argon are used as plasma-forming gas, propane, butane, methane, and acetylene are used as carbon precursors. Electron microscopy and Raman imaging show that synthesis products represent an assembly of flakes varying in the thickness and the level of deformity. An occurrence of hydrogen in the graphene flakes is discovered by X-ray photoelectron spectroscopy, thermal analysis, and express-gravimetry. Its quantity depends on the type of carrier gas. Quasi-one-dimensional approach under the local thermodynamic equilibrium was used to investigate the evolution of the composition of helium and argon plasma jets with hydrocarbon addition. Hydr...
Journal of Physics D: Applied Physics, 2019
Results of experimental study of the one-step plasma-based process of the synthesis of unsupporte... more Results of experimental study of the one-step plasma-based process of the synthesis of unsupported graphene and hydrogenated graphene are presented. A direct current (DC) plasma torch is used, the pressure is held at 350 Тоrr, and the flow rates of plasma forming gas (helium) and carbon source (propane–butane mixture) are kept constant. An influence of reactor geometry on the properties of synthesized product is investigated. Graphene and hydrogenated graphene were synthesized in an appreciable rate in the plasma jet volume under equal conditions using cylindrical and conical reactors accordingly. Synthesized graphene materials are characterized using electron microscopy, Raman spectroscopy, x-ray, and XPS analysis, confirming the existence of graphene and of hydrogenated graphene (graphane). In order to examine an influence of input parameters on the process of the synthesis of graphene materials, the quasi-1D numerical flow model is used to calculate the distributions of temperature and velocity within the reactor channel. The key role of the temperature distribution within the reactor in the synthesis of graphene materials is established. Cylindrical flow channel provides higher temperatures compared with the conical channel. It affects the flow composition at the outlet. Under lower temperature, the flow contains in addition to condensed carbon a great amount of hydrocarbons CH, which is favorable for the production of hydrogenated graphene. Under higher temperature, the pure graphene is synthesized, since the outlet flow has the carbon mainly in the condense phase, the quantity of CH being insignificant.
Fuel, 2018
A method for the combustion organisation in the cylinder of an HCCI engine is proposed. This meth... more A method for the combustion organisation in the cylinder of an HCCI engine is proposed. This method is based on the selective impact of electrical discharge in the form of a high frequency corona. The discharge is switched on at a certain crank angle and affects the mixture for a short time (a few rotation degrees of the crankshaft). The aim of the given study was to clarify how the discharge affects the low temperature combustion (LTC) stage to control the inflammation in an HCCI engine. It was shown that the best discharge impact timing is the beginning of the low temperature heat release (LTHR) or intermediate temperature heat release (ITHR) stages. The discharge does not directly ignite the mixture but only "pushes" the beginning of these stages and promotes their more rapid passing, controlling the heat release. It is mostly due to the dissociation of fuel and oxidiser, instead of heating the area of impact. Consequently, a non-equilibrium discharge can control the combustion timing, which is especially important in the case of a cold start or use of a lean mixture that is characterised by misfiring. It has been shown that the combustion timing after the top dead centre depends on the energy deposited into the injected mass of the fuel-air mixture treated by the discharge and the discharge switching on time. The dependence of the concentrations of NO x , CO, and unburned hydrocarbons on a specific deposited energy and the initial conditions is presented. The chemical kinetic mechanism of a selective discharge effect is revealed. The numerical simulation has been performed for the equivalence ratio ϕ = 0.33-0.5 and the intake temperature T in = 360-400 K in a propane-air mixture.
34th AIAA Plasmadynamics and Lasers Conference, 2003
ABSTRACT
33rd Plasmadynamics and Lasers Conference, 2002
35th AIAA Plasmadynamics and Lasers Conference, 2004
44th AIAA Aerospace Sciences Meeting and Exhibit, 2006
ABSTRACT
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Papers by Aleksey Bocharov