Specific features of thermal deforming of composite inductors during magnetic-pulse processing of materials

The problem of taking into account a non-stationary inhomogeneous temperature field in the analysis of the stress-strain state of inductor systems for magnetic-pulse processing of materials is considered. It follows from the analysis of open information sources that the problem of analyzing a non-stationary temperature field arising from the presence of a non-uniform electromagnetic field and its effect on deformation has been sufficiently studied in relation to induction heating. At the same time, during other operations of magnetic-pulse processing of materials, heating of equipment can cause additional deformations of a significant magnitude, which, in turn, can lead to a loss of equipment performance due to destruction or irreversible deformation. A general approach to the analysis of such problems is proposed, which involves the determination of the spatial-temporal distributions of the quantitative characteristics of the electromagnetic field, temperature field and stress-strain state. The necessity of using numerical methods for carrying out such an analysis has been substantiated. The most effective numerical method is the finite element method, which makes it possible to analyze the unsteady electromagnetic field, temperature field, and stress-strain state within the same calculation scheme. In this case, within the framework of the finite element method, iterative schemes can be created that allow taking into account nonlinear effects. Here, nonlinear effects can be due to the dependence of the mechanical and electro-physical properties of the material on temperature, the plastic nature of deformation, and the need to take into account contact phenomena. The results of complex analysis for a composite single-turn inductor with a dielectric band are presented. The features of contact interaction were taken into account by introducing layers of contact finite elements. The stress-strain state of the inductor is estimated for two variants of the materials used: copper and non-magnetic steel.

Heat generation in devices for magnetic-pulse processing of materials

The problem of analysis of non-stationary heat generation due to the flow of electric current in devices for magnetic-pulse processing of materials is considered. An analysis of the available information sources led to the conclusion that a large number of studies in this area are devoted to the study of heat transfer processes during technological operations of induction heating. In other technological operations of magnetic-pulse processing of materials, heat release is also significant. In this case, a non-stationary inhomogeneous temperature field can lead to significant temperature deformations. This, in turn, can cause a loss in the performance of the device due to destruction or irreversible deformation. Adequate modeling of non-stationary temperature propagation in this case is an obligatory step in carrying out computational analysis in the process of designing technological devices. A general strategy is proposed for determining the propagation of a non-stationary temperature field in the presence of a non-stationary non-uniform electromagnetic field. The proposed strategy presupposes a general solution of the problems of the propagation of the electromagnetic field and the temperature field within the framework of a unified design scheme. The use of the finite element method is proposed as a numerical method. The finite element method, when used in such problems, allows one to draw up iterative procedures that can be used to take into account the nonlinear effects associated with the influence of temperature on the electro-physical properties of materials. The problem of sequential determination of a non-stationary, non-uniform electromagnetic field and a non-stationary temperature field in composite matrices intended for electromagnetic pressing of powders of super-strong refractory materials is considered. The distribution of some quantitative characteristics of the electromagnetic field, as well as the dependence of temperature on time are presented.

Application and schemes of induction preliminary heating in magnetic-pulse treatment of metals

The features of the processes of magnetic-pulse processing of metals in traditional schemes of technological processes of modern industrial production are highlighted. The work is a brief description of the state, application, and also proposed induction pre-heating schemes in industrial magnetic-pulse processing of metals. A method for increasing the efficiency of performing specified production operations is considered. The use of preheating leads to a significant improvement in the quality of production operations while reducing energy consumption. New directions of magnetic-pulse processing of metals are noted, implying the transformation of the natural repulsive forces of the metal of the processed object into the forces of magnetic-pulse attraction with a decrease in the operating frequencies of the acting fields. A significant decrease in operating frequencies makes it possible not only to go from repulsion to attraction, but also to go from working with ferromagnetic metals to non-ferromagnetic ones. For example, it becomes possible to attract aluminum blanks. Examples of the use of induction heating of metal blanks in modern industry are given. Various devices used for these operations, offered on the modern market, by both domestic and foreign manufacturers, are considered. The physics of Lenz-Joule heat release is described, the result of which is the induction heating of conductors by Foucault currents in the external electromagnetic field of the instrument. Schemes are proposed for the practical implementation of preliminary induction heating during magnetic-pulse processing of metal blanks, allowing the use of both autonomous devices for exciting eddy currents and a stationary connection, for the same purpose, of an additional source of electricity. As a result of the work, the possibility of increasing the efficiency by increasing the plasticity of the metal when heating the workpiece, as well as possible limitations of the described technology associated with an increase in the active resistance of metals with an increase in the Lenz-Joule heat release is noted.

Effects of electric pulse processing in increasing the efficiency of cotton oil from technical seeds

This article provides an analysis of the global demand for cottonseed oil consumption, the growing trend of cottonseed oil production and methods of obtaining vegetable oil based on modern technologies. Based on the results of the analysis, the electro technology of electric pulse processing of seed pulp was proposed to increase the efficiency of obtaining cottonseed oil from technical seeds. Experiments have shown that the maximum degree of damage to the seed nucleus by electric pulse treatment depends on the amount of oil extraction. It is also possible to reduce the roasting temperature of electrically pulsed seed pulp to 70-75 °C, and these parameters are considered be energy-saving parameters. It is possible to increase the amount of oil extracted from the seed and reduce energy costs in the technology through electro-pulse processing.

The Dependence of the Deviation of the Output Stabilized Current of the Resonant Power Supply during Frequency Control in the Systems of Materials Pulse Processing

The calculated dependences for determining the deviation of the output current of the resonant power supply of the materials pulsed processing system from a given stabilized value are obtained. The inversely proportional dependence of the output current on the frequency at the input of the series resonant circuit is obtained. These dependencies can be applied for the frequency control of the inverter’s switches commutation which stabilizes the RMS value of the output current. At the close to short circuit modes, the deviation of the output current from the stabilized value does not exceed 2%, and therefore it can be ignored.