Coriolis force impact on lump kinematics in a grinder workspace

Research relevance. Currently produced rotary grinders are not efficient enough, while their efficiently is mainly characterized by the degree of fineness. This is due to sparse knowledge of the processes occurring in the counter-impact labyrinth rotor when the material is being ground, and therefore insufficient scientific substantiation of the design methods. The grinding member’s geometry and rotation speed have been set empirically according to the similarity principle, which inevitably results in grinding fineness and efficiency deviation from the set values. It seems impossible to improve the design and therefore the running efficiency of the equipment unless the kinematics of a lump in the channel of the grinder is analyzed. Particular attention should be paid to the Coriolis force impact on the kinematics of a lump. It will make it possible to scientifically substantiate the dependence between equipment design and technological parameters. Methods of research included the factor analysis, data synthesis, and methods of mathematical and physical modeling. Object of research is a rotary grinder preparing rocks for sampling. Subject of research is the workflow of the counter-impact rotary grinder. Research objective is to increase the efficiency of the ore rotary grinder by analyzing particles movement in the rotor channels. Methods of research includes the analysis of particles motion in the rotor channels using the provisions of theoretical mechanics and the theory of impact. The differential calculus acts as a mathematical apparatus. Results and summary. Based on the proposed particle motion theory analysis and qualitative representations of the processes in the rotor of the counter-impact grinder, it is essential to form the foundation to obtain quantitative dependencies for design calculations. This will improve the methods of design and construction of a new type of rotary grinder. It was found that the Coriolis force reduces the relative speed of a lump by not more than 20.3% depending on the assumptions made

Assessment of the resistance of technical means of space systems and complexes to the effects of electrostatic discharges

In order to further improve the methods of protecting the onboard spacecraft equipment from the effects ofelectrostatic discharges, based on a comprehensive study of the problem of the occurrence of electrostatic discharges, theauthors carried out the studies described in this article to analyze the functioning of the onboard spacecraft equipment under the influence of electrostatic discharges. In the course of the research, the methodology for assessing the resistance ofthe onboard equipment of the spacecraft to the effects of electrostatic discharges was refined, based on the generalization of the calculation and analytical work. The analysis of the resistance of the onboard equipment of the spacecraft was carried out taking into account the main mechanisms of the effect of electrostatic discharges on the onboard space network. Taking into account the need to assess the resistance of the onboard space network equipment to electrostatic discharges outside real operating conditions, the authors assess the resistance of the onboard space network equipment on the basis of mathematical and physical modeling. Asaresult of the study, an algorithm was developed for assessing the resistance of the onboard equipment of a spacecraft to the effects of electrostatic discharges, which is described in detail in this article.

Geological and mining-engineering peculiarities of implementation of hydromechanical drilling principles

Purpose. Substantiation of the design solutions in separate units of the modernized hydromechanical devices and specification of rational technological modes of their operation in specific geological and technical conditions. Proposals on construction of wells by development and introduction of progressive methods and techniques. Methodology. Analysis of the peculiarities of the modernized hydromechanical drilling devices in terms of rock breaking is performed using modern methods of analytical analysis and experimental research, i.e. by using mathematical and physical modeling; method of modeling and processing of research results in the SolidWorks medium and others; control and measuring tools and materials. The process of solving the problems of optimal planning of the experiment was divided into four stages: development of a planned model; preparation of the necessary initial data; calculation of the model; obtaining and processing of the results. The well rock-breaking processes were modeled on a special-purpose laboratory stand equipped with a measuring and control unit (flow meter, manometer, tachometer, and coordinate spacer). Findings. The main ways to improve well hydromechanical technologies have been identified. The fundamental principles have been formulated concerning the process of design of such equipment schemes that will combine the most productive and efficient methods of the rock mass operations. A number of factors characteristic of the implementation of well hydromechanical technologies, have been identified, i.e.: rational range of physical properties of rocks according to which proper technical and technological characteristics of the devices are selected; structural use of mechanical rock-breaking organs of the devices; and operating parameters of the drilling process. It has been proved that the developed design schemes of hydromechanical drilling devices, in terms of their optimal technical performance and technological development, can be recommended for their use in the appropriate geological and technical conditions, where the implementation of other methods is inexpedient or limited. Originality. Formation of the peripheral part of the bottomhole is a subordinate factor determined by the device design; effective profiling is possible only due to the introduction of additional components into the hydromechanical drilling devices, which makes it possible to use certain technological methods. Practical value. The obtained results of laboratory and analytical studies are basic to design operating parameters of the well deepening processes by using the hydromechanical devices. Data from the study on bottomhole working processes of hydromechanical technologies are the starting point for the substantiation of design and technological parameters of modernized pellet impact devices.

PHYSICAL AND MATHEMATICAL MODELING OF THE WAVE QUENCHING CHAMBER WITH THE UPPER PART IN THE FORM OF A PERMEABLE WATERFRONT

This paper presents the results of mathematical and physical modeling of the interaction of waves with the wave chamber on cylindrical supports and the upper part in the form of a permeable waterfront. On the basis of the diffraction model the mathematical modeling of refraction and transformation of waves near the structure is carried out. In the presence of a structure, the transformation of waves is co-accompanied by the phenomena of wave destruction at the edges of the structure and the partial reflection of residual waves from the walls of the protective front. Reflection phenomena cause changes in wave heights along the front of the structure. The results of experimental data are given, which showed that the structure with such a construction is resistant to waves, large soil erosion was not observed.

Advances in Sintering of Iron Ores and Concentrates

Chapter “Sintering of iron ores and concentrates” is focusing on the study of theoretical, thermodynamic and experimental results in the production of sinters from iron ores and concentrates. The authors of the chapter have long been interested with the production of sinter from iron ores and have recently also focused on the use of biomass as a substitute for a part of coke breeze in the production of iron sinter. Important characteristics of the chapter include the characteristics of iron ores and concentrates used to produce sinter including physico-chemical, mineralogical and metallurgical properties. Predicting the influence of the properties of iron ores and concentrates on the final quality of the sinter and on the production of pig iron is another part of the study. These properties are a key factor in achieving the highest possible agglomerate quality for pig iron production. The sintering process requires mathematical and physical modeling. For this reason, the authors created thermodynamic models of sintering including material-heat balance of sinter production. In the final part of chapter is the use of traditional and alternative carbonaceous fuels in the production of sinters, mainly in the context of replacement of coke breeze with biomass.