Search results for "Furnace"
showing 10 items of 44 documents
Influence of the channel design on the heat and mass exchange of induction channel furnace
2011
PurposeThe purpose of this paper is to present in‐depth numerical modelling of heat and mass exchange in industrial induction channel furnace (ICF).Design/methodology/approachThe turbulent heat and mass exchange in the melt is calculated using a three‐dimensional (3D) electromagnetic model and a 3D transient large eddy simulation method. The simulation model has been verified by flow velocity and temperature measurements, which were carried out using an industrial sized channel inductor operating with Wood's metal as a low temperature model melt.FindingsThe ICF is well‐established for melting, holding and casting in the metallurgical industry. But there are still open questions regarding th…
Numerical studies of the melting process in the induction furnace with cold crucible
2008
PurposeAims to present recent activities in numerical modeling of cold crucible melting process.Design/methodology/approach3D numerical analysis was used for electromagnetic problem and 3D large eddy simulation (LES) method was applied for fluid flow modeling.FindingsThe comparative modeling shows, that higher H/D ratio of the melt is more efficient when total power consumption is considered, but this advantage is held back by higher heat losses through the crucible walls. Also, calculations reveal that lower frequencies, which are energetically less effective, provide better mixing of the melt.Originality/value3D electromagnetic model, which allows to take into account non‐symmetrical dist…
Solid inclusions in an electromagnetically induced recirculated turbulent flow: Simulation and experiment
2014
Abstract The paper presents the numerical and the experimental investigation of the particle-laden recirculated turbulent flow of liquid metal that is driven by electromagnetic force. Such flow is typical for induction metallurgical furnaces. The paper describes the behaviour of solid spherical particles that are mixed in the flow from a top surface of a melt and covers 3 stages of an admixing process as well as deposition of inclusions on the wall of a vessel. Experimental investigation of particles concentration at the quasi-stationary stage is fulfilled on the basis of a novel idea: ferromagnetic particles are proposed as a physical model of non-conductive inclusions in liquid metal at t…
Gas-phase supersaturation effects on morphology properties of ZnO nano and microstructures grown by PVT
2016
A systematic study of the morphology evolution of ZnO nanostructures grown by physical vapour transport was carried out. The evolution of the shape with the growth time is shown to depend on the different gas-phase supersaturation and temperature conditions encountered in the crystallization zone of the tube furnace. The observed morphology transitions are discussed, and a growth model for ZnO nanostructures is given.
Iron metallurgy, political economy and social change during the first millennium BC in eastern Iberia
2020
Analizamos las dinámicas históricas de adopción y uso social de la metalurgia del hierro entre los ríos Ebro y Segura a lo largo del primer milenio a.C. Diferentes escalas de análisis, desde los contextos rituales hasta los patrones de asentamiento o la organización interna de los poblados, nos permiten identificar diversas etapas: los primeros objetos de hierro en la zona fueron bienes de prestigio que circularon en un marco de conexiones mediterráneas a partir de los siglos XII-XI a.C. La actividad siderúrgica en la zona se documenta a partir del siglo VIII a.C., con la instalación de población de origen fenicio en asentamientos costeros. La generalización del hierro se producirá a partir…
Analysis and Design of Induction Liquid Metal Processes Using Advanced Numerical Modelling
2019
Comprehensive knowledge of the turbulent flows, heat and mass transfer processes in the melt of induction applications is required to realize efficient metallurgical processes. Therefore, the process oriented development, design and optimization of induction furnaces for melting and casting of metals require praxis oriented simulation and analysis of the complex in-stationary turbulent melt flows and temperature distributions as well as the heat and mass transfer processes in the liquid metal. The studies, presented in this paper, demonstrate the possibilities of using advanced three-dimensional transient numerical modelling for successful simulation of the melt flow as well as heat and mas…
Particle transport in recirculated liquid metal flows
2008
PurposeAims to present recent activities in numerical modeling of turbulent transport processes in induction crucible furnace.Design/methodology/approach3D large eddy simulation (LES) method was applied for fluid flow modeling in a cylindrical container and transport of 30,000 particles was investigated with Lagrangian approach.FindingsParticle accumulation near the side crucible boundary is determined mainly by the ρp/ρ ratio and according to the presented results. Particle settling velocity is of the same order as characteristic melt flow velocity. Particle concentration homogenization time depends on the internal flow regime. Separate particle tracks introduce very intensive mass exchang…
Physico-chemical evolution of low-pH cements : influence of the temperature and the retention mechanisme of alkalins
2010
Because of their high alkalinity, Portland cement (OPC)-based materials may have deleterious effects in an underground waste repository. A solution would be to use low-alkalinity cements (also referred as low-pH cements) generating interstitial solutions with a reduced pH (11 instead of 13.5 for OPC), and thus showing an improved chemical compatibility with the repository environment. In this work, the investigated formulations were based on binary (OPC / silica fume) or ternary (OPC / silica fume / slag or fly ash) blends, with high substitution levels of CEM I (from 30% to 80%). This research project met two main objectives: (i) study the chemical evolution of low-pH cements at 50°C or 80…
Microwave muffle furnace assisted decomposition of vegetable samples for flame atomic spectrometric determination of Ca, Mg, K, Fe, Mn and Zn
1992
Calcium, magnesium, potassium, iron, manganese and zinc can be accurately determined in vegetable samples by flame atomic absorption and flame emission spectrophotometry after a previous dry ashing of the sample in a microwave muffle furnace. This treatment is carried out in 45 min using a new accessory developed by us to obtain high temperatures on a domestic microwave oven. Sample ashes, obtained in the muffle, are diluted with nitric acid and the obtained slurry is introduced directly into an air-C2H2 flame for the analysis of Fe, Mn, and Zn, or injected into a double-channel FIA manifold to determine Ca, Mg and K. The obtained results agree with those certified and also with those obtai…
Improvements in aggregate-paste interface by the hydration of steelmaking waste in concretes and mortars
2019
[EN] The objective of the experimental work is to study the mechanical properties in self-compacting concretes (SCC) in which part of the limestone aggregate has been replaced by granulated blast furnace slag (GBFS) in different percentages ranging from 0% to 60%. The results show that at early ages the SCC with the largest content in slag tend to have lower compressive strengths due to the poor compacting of the aggregates, although in the long-term their strength increases due to the reactivity of the slag. In fact, at the age of 365 days, the mortars made with the substitution of 50% of cement by ground GBFS reach compressive strength similar to that of the mortar made with 100% of cemen…