The published articles discuss models of real and hypothetical ERF; the information about transitional and stationary processes is in graphic and video form. Most of the models are not supplied with detailed explanations about the thermo-physical and mass-geometric parameters of the arrangements. The table below shows several processes which illustrate the realization of thermal processes through systems of DE and FEM.
The topic under consideration, "Analysis and Modeling of Electro-Thermal Processes and Devices (electric resistance furnaces of periodic action)", refers to the problems of transitional and established processes in electric resistance furnaces, the solution of these problems through numerical methods and the analysis of the obtained results. This is necessary to be done in order to obtain conditions for optimization of the constructions under various criteria that make the basis of a design methodology. The problems thus defined can be solved by using software, whereby the picture of the temperature field is obtained in graphic form through computer simulation of the transitional processes of heating and cooling. This treatment is based on the main physical laws of heat conductivity, and the principles of operation for furnaces of this type with application of numerical methods numerical methods.
The formulation of this topic as presented by us refers to a wide range of problems in furnace building.
Owing to the considerable improvement of insulation and construction materials, it is possible to build facilities with much better technical characteristics. In parallel with this, however, problems occur with the operative modes and the progress of transitional processes - they may develop at very high speeds which in certain cases are inadmissible. Besides, using materials at the upper limit of their functionalities require a very precise maintenance of the assigned operative mode, which is impossible to assess by criterial of graphic correlations. Modern technological operations concerning thermal treatment of details also require strict observation of certain conditions and, above all, maintenance of temperature modes with very narrow limits of fluctuation.
In view of contemporary mathematical achievements in the area of numerical methods, it is now possible to solve problems which used to require either considerable practical experience or complex graphic-analytical methods.
It is evident that there is a need for an integral scientific approach enabling analysis of the post-design processes prior to their practical realization in a facility, or - if the facility already exists - defining the limits of its operability. This is done using models developed in congruence with the physical processes and constructive specificities of a particular unit and tested on other, already existing facilities.
An integral treatment of this problem will be an asset to companies manufacturing electric resistance furnaces; it will also boost the quality of industrial technological processes in companies operating such equipment.
The topics presented here with regard to design and operation of ERF comply with the contemporary requirements on integral research of various facilities via mathematical models. In these cases they have to correspond to the physical processes taking place inside the facilities and around them. The realization of the model, the analysis of the processes and their comparison with experimental and other results prove its viability and functionality for application both in theoretical and practical environment. This model of ERF, developed and subjected to multifaceted testing using relevant software, gives us the ground to draw the following conclusions about the accomplishment of the assigned tasks in the context of the entire work:
1. The models of chamber and blast ERFs thus created enable the analysis of the construction elements and processes of operation in a facility. We have demonstrated specific features, associated with ERF design (door, walls of ERF, temperature sensor and others) and their operation, by applying thermal processes modeling (via Finite Element Method and systems of DE). The models are supported by experiment.
2. A method has been presented to obtain the temperature field as a result of finite effects and to determine the areas with assigned irregularity of the temperature field for chamber and blast ERFs. This method enables us to determine well in advance the dimensions of that part of the operative space where a certain technological process will take place.
3. An analysis has been presented of the system resources in their simulated realization depending on the construction parameters of the furnace. This analysis is the basis on which to make recommendations on numerical methods relevant to use.
4. A complete analysis has been presented of the losses, including the quantity of heat accumulated in the walls or given out into the environment during the technological process. This analysis enables making an entire energy analysis of a facility as a function of its operative modes:
- at the stage of design: compliance with the customer's requirements.
5. A modified methodology has been suggested for ERF design based on the models thus developed. The practical application of this methodology is supported by its implementation by manufacturing companies. The said methodology eliminates some disadvantages of the morally obsolete graphic-analytical approach. It is advisable that the used models of the thermal assembly should accompany the technical documentation of the device. In this way the accomplished design activities are helpful in further exploitation.
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