Optimal control for a phase field model of melting arising from inductive heating

<abstract><p>Due to its unique performance of high efficiency, fast heating speed and low power consumption, induction heating is widely and commonly used in many applications. In this paper, we study an optimal control problem arising from a metal melting process by using a induction heating method. Metal melting phenomena can be modeled by phase field equations. The aim of optimization is to approximate a desired temperature evolution and melting process. The controlled system is obtained by coupling Maxwell's equations, heat equation and phase field equation. The control variable of the system is the external electric field on the local boundary. The existence and uniqueness of the solution of the controlled system are showed by using Galerkin's method and Leray-Schauder's fixed point theorem. By proving that the control-to-state operator $ P $ is weakly sequentially continuous and Fréchet differentiable, we establish an existence result of optimal control and derive the first-order necessary optimality conditions. This work improves the limitation of the previous control system which only contains heat equation and phase field equation.</p></abstract>

Transport phenomena and evolution mechanism of the melt pool during a laser based metal melting process

This article presents a fully three-dimensional numerical study on the process of melt pool evolution. In order to overcome the simplifications used in many existing studies, an enthalpy method is developed for the phase change, and an accurate interface capturing method, i.e., the coupled volume-of-fluid and level set (VOSET) method, is employed to track the moving gas-liquid interface. Meanwhile, corresponding experimental studies are carried out for the purpose of validation. The obtained numerical results show the formed interface morphology during the process of melt pool with its typical sizes and are quantitatively consistent with those data measured in experiments. Based on the numerical results, the thermodynamic phenomena, induced by the interaction between heat and momentum exchange, occurring in the formation of melt pool are presented and discussed. Mechanisms of the melt pool evolution revealed in the present study provide a useful guidance for better controlling the process of additive manufacturing.

Development of Technology Ferrous Metal Melting Furnace Ancient Times in Indonesia

Technological knowledge of the use of metals is inseparable from human knowledge in the processing pyrotechnics of fire as a power in high temperature processes for producing objects. The fire is used for smelting and casting in melting furnaces. Metal smelting furnace is a heat production device, which is used to purify the metal, in this case iron. This paper aims to determine the development of ferrous metal smelting furnace technology in Indonesia with the library research method from the results of previous studies. Based on the results of the analysis, there are four technologies for smelting iron, namely pit kiln, bloomery furnace, blast furnace, and induction furnace. Of the four technologies, three are in use in Indonesia, namely bloomery furnace, blast furnace, and induction furnace.

Technology as a factor in the cultural development of mankind: a study of the production nature of primitive culture

Purpose of article. Explore technological progress in the context of the development of a primitive culture. The methodology is based on an integrated approach and relies on analytical (when analyzing philosophical, art history, cultural studies literature on the subject of research), historical (when clarifying the stages of development of primitive culture), and conceptual (when analyzing the role of technology in the cultural development of mankind) research methods. The scientific novelty of the article lies in the fact that for the first time the formative role of technology in the cultural development of mankind is investigated, and also the cooperative nature of the production of artifacts of primitive culture is determined. Conclusions. As a result of the study of archaeological finds of primitive culture, it has been established that in the course of cultural evolution, tools of labor have become cultural artifacts, works of art. The emergence of production technologies (stone processing, fire control, metal melting) radically transformed the specifics of the organization of production activities, and therefore changed the course of cultural development. Therefore, in the course of the study, the formative role of technology in the formation of artistic culture was proved.

Influence of Selected Model Parameters on the Electromagnetic Levitation Melting Efficiency

The article presents the results of multivariate calculations for the levitation metal melting system. The research had two main goals. The first goal of the multivariate calculations was to find the relationship between the basic electrical and geometric parameters of the selected calculation model and the maximum electromagnetic buoyancy force and the maximum power dissipated in the charge. The second goal was to find quasi-optimal conditions for levitation. The choice of the model with the highest melting efficiency is very important because electromagnetic levitation is essentially a low-efficiency process. Despite the low efficiency of this method, it is worth dealing with it because is one of the few methods that allow melting and obtaining alloys of refractory reactive metals. The research was limited to the analysis of the electromagnetic field modeled three-dimensionally. From among of 245 variants considered in the article, the most promising one was selected characterized by the highest efficiency. This variant will be a starting point for further work with the use of optimization methods.

Role of amount of council and diameter of copper on metal smelting temperature

This paper discusses the role of the number of turns and the diameter of copper wire on metal melting temperature. The aim is to determine the effect of the number of turns and wire diameter on the temperature produced in the metal smelter. The method used by testing using the number of turns referred to is 20 turns, 25 turns, 30 turns, and a wire diameter of 1 mm, 1.5 mm and 2 mm. The results of the average value of the number of turns that vary, where the number of turns (30) has the highest average temperature value of 681.11 ° C, while the number of turns (25) produces the lowest average temperature of 648.22 ° C, the number of turns (20) the averagetemperature value is 651.11 ° C. and the larger the coil wire diameter is used, the higher the temperature produced. At 2mm, the coil wire diameter has the highest average temperature value of 691.11 ° C, while the coil wire diameter of 1.5mm has the highest average temperature value of 691.11 ° C. The average temperature value is 667.22 ° C, then the coil wire diameter of 1 mm has the lowest average value of 622.11 ° C