Numerical Modeling of Physical Fields in the Process of Drying of Paper for Corrugating by the Infrared Radiation

By using a numerical model, developed based on the proposed physical and mathematical models, we performed a numerical study of non-stationary temperature fields and moisture content of the process of infrared radiation drying of fluting. A distinctive feature of present study is a combined consideration of the kinetics of drying process, translucency to the IR radiation of the material using the approximations of the Burgers' models, "gray" medium and diffuse reflection of boundaries. Verification of the numerical model demonstrated a convergence of results of numerical modeling of the fluting surface temperature, duration and speed of its drying with the data of physical experiment within the range of 5 % on the interval of change in the square meter mass of dry fluting from 0.112 kg/m2 to 0.2 kg/m2. It is substantiated that the developed numerical model makes it possible to define kinetic patterns and basic parameters required to intensify the process of drying and to design the appropriate equipment

Investigation of the Current State of Isostatic Graphite Production Technology

The study of isostatic graphite production process and its development trends in the world market was conducted.It was established that the isostatic graphite production is a complex and multistage process that requires careful preparation of raw materials, the usage of powerful specialized pressing equipment, the use of elaborate heat treatment modes etc. As a result, it creates a high final price comparing to other brands of graphite materials.Methods of synthesis, analysis and systematization of available information regarding the isostatic graphite production were used for the study.The peculiarities of foreign isostatic graphite production technology were determined, which allows to set directions of improvement by Ukrainian producers, namely:- choice of components and their composition for coke and pitch mixture;- adding special modifiers;- optimization of particle size distribution of the filler;- setting the pressure for pressing moulding powder;- choice of modes of blanks thermal processing etc.The level of future growth in global demand is determined for isostatic graphite materials and products based on it, which is more than 5 % of the annual global volume of production.The results enable further research in order to develop equipment and rational modes of grinding, mixing and pressing coke-pitch compositions using available Ukrainian brand coke and pitch. Furthermore, it will allow in the future to conduct a study of pressed billets heat treatment to reduce the unit cost of electricity and improve the process of isostatic graphite material manufacturing

Modeling and Analysis of the Process of Polymeric Film Cooling on the Drum with a Liquid Cooling Agent

Using the developed mathematical model, we performed an analysis of the process of cooling an extruded polymeric film on the drum with inner cooling. Dependence of average and local temperatures of a polypropylene film and the drum's shell under condition of drum's settling under stationary thermal mode was studied. It was shown that temperature difference between the surface of the shell and the refrigerant in the drum at film cooling can reach 40–65 °C and higher, which affects intensity of cooling of a polymeric film. With an increase in the minimum thickness of a film and (or) a decrease in its velocity, the influence of drum's warm-up on the intensity of film cooling increases. Ignoring the drum's warm-up process can lead to the insufficient cooling of a polymeric film and thus, to a decrease in its quality. The developed mathematical model could be used to analyze the process of cooling of not a film only, but also of other roll polymeric materials, obtained both by extrusive and rolling-calender method

Modification of Implicit Algorithm for Solving a Problem on the Elastic Plasticity of Bulk Materials

A mathematical statement is given of the elastic-plastic behavior of isotropic bulk material using a classic model of Drucker-Prager. We have improved the return-mapping algorithm for solving numerically a problem on the mechanical state of bulk material. In order to solve a system of nonlinear equations by the Newton method, it is proposed, at each step of iterations, instead of finding the inverse matrix, to solve a system of algebraic equations, linearized by Newton, by applying the Gauss exclusion method. This makes it possible to reduce the number of arithmetic operations by about 3n2 (n is the dimensionality of SLAE) at each iteration step for each plastic finite element. We have tested the programming code developed on the high-level programming language Fortran on the example of a model material, characterized by the associative law of current, at different values of the angle of natural repose. Comparison of the obtained results of numerical experiment with the data received by applying the proprietary software revealed a deviation within 0.25–5.3 % depending on the desired magnitud

Determination of Parameters of the Carbon­containing Materials Gasification Process in the Rotary Kiln Cooler Drum

An assessment of the feasibility of using the existing equipment of a rotary kiln cooler drum for heat treatment of a carbon-containing filler to produce synthesis gas using production waste in the form of a dust fraction of heat-treated petroleum coke or anthracite is carried out. A mathematical model of the process of gasification of carbon particles is formulated in the continuous-discrete formulation, including thirteen global reactions, of which four are heterogeneous and nine are homogeneous. A numerical model of gasification of a dust fraction of a carbon-containing filler in the rotary kiln cooler drum in the axisymmetric formulation is developed. The convergence of the numerical solution of the gasification problem by the grid step is investigated. It is found that the computational grid, which includes 73,620 cells and 75,202 nodes, leads to an error in determining the main parameters of the model of no more than 1–2 %. Verification of the developed numerical model is performed. It is found that the difference between the molar fractions of CO and H2, the values of which were obtained by various software products (Fluent, NASA CEA), is in the range of (2.8...5.8) %. Using the developed numerical model of the process of gasification of a carbon-containing filler in the rotary kiln cooler drum, the quantitative composition of the combustible components of the syngas for different initial parameters is determined. It is found that with the ratio О2/С=(42.7...51.6) %, the predicted quantitative composition of the combustible gases of synthesis gas in molar fractions is СО=(32.8...36.9 )%, Н2=(17.1...18.4) % and CH4=(0.03...0.16) %. The possibility of using the NASA CEA program, intended for operational calculations of equilibrium chemistry, for engineering calculations of the material composition of synthesis gas of industrial furnace equipment, is show