The demand for up-to-date building materials and components for their production is constantly growing. The purchasing of foreign analogues is often unreasonable and costly, and the domestic products not always meet the high requirements specified for them. In light of this, it is necessary to develop up-to-date knowledge-intensive technologies of producing building materials of various purpose, as well as materials and products of ceramic, varnish- and-paint, glass and other industries, the basis of which is the application of high-dispersive powders. The extensive use of fine-ground and ultrafine-ground materials resulted in designing a wide range of grinders of various types (ball, vibration, planetary, centrifugal, jet grinders etc.). In each certain unit the special conditions for grinding are created, which allows using them for processing materials with various physical and mechanical characteristics. In this work the mathematical model of closed grinding cycle with combined-action air separator is suggested. In this model the integral functions of partition in air separator have been obtained. The calculated and experimental values of the integral functions of partition in air separator have been compared.
To solve the problem of obtaining superfine materials, a mathematical model of materials dispersion is proposed. The model uses the Focker-Planck equation to determine the probability density. The physical density of the probability density is interpreted as a differential characteristic of the composition of the ground material. The closure is performed using the equations of material balance and limitations that ensure the performance of low-tonnage technological complexes. Criteria for the controllability of the grinding process are proposed. These criteria take into account the random nature of the processes and the existing disturbances in the chamber of the vortex-acoustic disperser. In this case, the vortex-acoustic disperser in the working range of changing its parameters is considered as a complex physico-mechanical system. The developed mathematical model makes it possible to study the laws of the grinding process in a vortex-acoustic disperser. The model also makes it possible to find the optimal design and operational parameters of the disperser.
Аннотация: Представлен анализ аппаратов для пневмомеханического гра-нулирования техногенных материалов. Исследовано движение частиц техноген-ных порошкообразных материалов в воздушном потоке под действием центро-бежных сил. Рассмотрена совокупность сил, действующих на частицу в процессе движения материально-воздушного потока в торообразной камере. Представлено математическое описание и траектории движения частиц в газодисперсном потоке.Одним из перспективных направлений комплексной переработки техноген-ных порошкообразных материалов различных отраслей промышленности (хими-ческой, строительной, топливной, пищевой, агропромышленного комплекса и др.) является гранулирование полидисперсных смесей [1]. В настоящее время извест-но большое разнообразие аппаратов для гранулирования полидисперсных мате-риалов: тарельчатые; барабанные; псевдоожиженного и фонтанирующего слоя; вибрационные, центробежные, грануляторы -сушилки -классификаторы и др. [2].В связи с интенсивным развитием эффективных технологий замкнутого цик-ла переработки материалов (рециклинга), а также созданием в сфере научно-технического предпринимательства малотоннажных технологических комплексов [3 -5] особое значение приобретают вихревые аппараты для микрогранулирова-ния полидисперсных смесей.Важное значение имеет реализация данными аппаратами следующих техно-логических возможностей:-способности к агломерации полидисперсных смесей с различными физико-механическими характеристиками (гранулометрией, плотностью, адгезионной способностью, сыпучестью и др.) входящих компонентов;-максимальной степени свободы турбулентного движения гранулируемых частиц и повышенной подвижности полидисперсных смесей в поле действия цен-тробежных сил;-совмещению в одном аппарате различных технологических операций (смешения, увлажнения, изменения величины динамического воздействия и др.);
The flow of fluids through pipes directly depends on the physicomechanical characteristics of the material. When designing technological equipment, it is assumed that the equipment operates with the limiting physical characteristics of the liquid. The study of the flow of non-Newtonian fluids is important for the development of energy-saving methods for the cement industry. In this paper, we study the flow of cement raw sludge through rigid pipes. It is shown that when moving in pipes near the pipe walls, the sludge moves like a normal Newtonian liquid, and near the pipe it moves like a solid. This indicates that when moving through a pipe with a prolonged non-stationary effect, the sludge behaves like a normal Bingham body. The article found the flow rate, the drag coefficient, the Reynolds number, and the hydraulic resistance when the sludge moves through the pipe. In this paper, the parametric law of resistance of sludge movement in pipes is defined, which can be considered as a convenient way to calculate pressure drop. It follows from the law that, when flowing through pipes, sludge now acquires the properties of a plastic body and behaves like Bingham plastic.
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