Проведено серію тестових розрахунків з оцінки придатності вільного відкритого програмного коду OpenFOAM для розв’язання термічних та електротермічних задач.
Modern requirements for development and modernization of equipment and processes are speed, accuracy, mini-mum costs. Usage of numerical simulation with latest achievements in computer hardware and software can pro-vide these requirements at the appropriate level. Numerical modeling allows one to quickly analyze new solutions and find the most effective ones. Also it can be apply for finding optimal value of input parameters or best process conditions. Computational simulation allows one to look deeper into physical phenomena or technological process-es. And it can determine the values that are difficult or impossible measured with experiment. Nowadays computer simulation has become a useful part of modeling many natural systems in physics, chemistry and biology as well as in engineering to gain insight into the operation of those systems. A lot of different softwares are used for purpose of numerical modeling. OpenFOAM is a good example of this class of software.
OpenFOAM (Open Source Field Operation and Manipulation) is a C++ toolbox for the development of customized numerical solvers, and pre-/post-processing utilities for the solution of continuum mechanics problems, including computational fluid dynamics (CFD). The code is released as free and open source software under the GNU Gen-eral Public License.
In this article, OpenFOAM is evaluated with regard to its suitability for the simulation of nonlinear heat conduction with and without heat source. In addition modified solver for modeling of electric heating of solid materials is pre-sented.
To validate OpenFOAM test cases were set up and the results were compared with commercial software that has similar computational capabilities and with theoretical data. Test cases: steady-state nonlinear heat conduction in multilayer plane wall; steady-state heat conduction with heat source in two cylinders in contact; Joule heating of 3 square rods with different thermal and electric properties.
The results obtained from OpenFOAM were in good agreement (near 1 %) with both numerical and analytical solu-tions.
Використовуючи експериментальні дані про електропровідність сипкого коксу та графітованих сумішей, одержано залежності, що дозволяють визначати питомий електричний опір залежно від вмісту сирого й графітованого коксу в суміші в діапазоні температур від 20 до 1000 °С, а також питомого електричного опору для сирого коксу й графітованої суміші залежно від її гранулометричного складу.
Using previously obtained experimental data on the electrical conductivity of bulk (carbon) coke and graphite mixtures obtained relationships to determine the value of specific electric resistance depending on the composition of crude coke and graphite in a mixture in the temperature range from 20 to 1000 °C. Also dependence of the electric support for raw coke and graphite convertible mixture depending on its grain size is obtained.
Study of the electrical resistivity of carbon materials relates to the field of saving energy in the furnaces of graphitization. Carbon materials are not only the raw materials for electrode manufacturing and coal products, but also are the active electrical resistivity in the furnaces of graphitization and can be recovery and thermal insulation. Resistance value allows drawing conclusions on the structural transformations that took place in the carbon material, caused by external influences on him. Electrical resistivity of the coal charge exhibits a significant influence on the uniformity of distribution of electric power in the volume of the furnace and has a direct impact on product quality and losses of energy.
Literature data of electrical resistivity of the coal charge can’t be used without additional analysis and calculations in different technological process conditions. The reason for this is the dependence of properties coal charge not only on the temperature range, but also on the particle size distribution of the starting materials and the degree of graphitization.
The article draws previously obtained experimental data on the electrical conductivity of particulate coke and graphite mixtures. Analysis of the experimental data showed that for the materials in question observed correlation of electrical resistivity particulate carbon materials on the particle size and the degree of graphitization.
The results of our study allow defining the magnitude of the electrical resistance depending on the composition of the mixture of raw coke and graphitized, the particle size of the starting components of the mixture at temperatures ranging from 20 to 1000 ºC.
The obtained dependences are necessary to find the optimal properties of the coal charge used in the production, as well as for the development of energy-saving regulations in technological processes of the enterprises.