scholarly journals Numerical Simulation on Motion Behavior of Inclusions in the Lab-Scale Electroslag Remelting Process with a Vibrating Electrode

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1784
Author(s):  
Fang Wang ◽  
Boyang Sun ◽  
Zhongqiu Liu ◽  
Baokuan Li ◽  
Shuo Huang ◽  
...  
Keyword(s):  
Vibration Frequency ◽  
Slag Layer ◽  
Continuous Phase ◽  
Filling Ratio ◽  
Electroslag Remelting ◽  
Discrete Phase Model ◽  
High Quality ◽  
Removal Ratio ◽  
Metallic Inclusions ◽  
Motion Behavior

In order to meet the requirement of high-quality ingots, the vibrating electrode technique in the electroslag remelting (ESR) process has been proposed. Non-metallic inclusions in ingots may cause serious defects and deteriorate mechanical properties of final products. Moreover, the dimension, number and distribution of non-metallic inclusions should be strictly controlled during the ESR process in order to produce high-quality ingots. A transient 2-D coupled model is established to analyze the motion behavior of inclusions in the lab-scale ESR process with a vibrating electrode, especially under the influence of the vibration frequency, current, slag layer thickness, and filling ratio, as well as type and diameter of inclusions. Simulation model of inclusions motion behavior is established based on the Euler-Lagrange approach. The continuous phase including metal and slag, is calculated based on the volume of fluid (VOF) method, and the trajectory of inclusions is tracked with the discrete phase model (DPM). The vibrating electrode is simulated by the user-defined function and dynamic mesh. The results show that when the electrode vibration frequency is 0.25 Hz or 1 Hz, the inclusions will gather on one side of the slag layer. When it increases from 0.25 Hz to 1 Hz, the removal ratio of 10 μm and 50 μm inclusions increases by 5% and 4.1%, respectively. When the current increases from 1200 A to 1800 A, the flow following property of inclusions in the slag layer becomes worse. The removal ratio of inclusions reaches the maximum value of 92% with the current of 1500 A. The thickness of slag layer mainly affects the position of inclusions entering the liquid-metal pool. As the slag layer thickens, the inclusions removal ratio increases gradually from 82.73% to 85.91%. As the filling ratio increases, the flow following property of inclusions in the slag layer is enhanced. The removal ratio of 10 μm inclusions increases from 94.82% to 97%. However, for inclusions with a diameter of 50 μm, the maximum removal ratio is 96.04% with a filling ratio of 0.46. The distribution of 50 μm inclusions is significantly different, while the distribution of 10μm inclusions is almost similar. Because of the influence of a vibrating electrode, 10 μm Al2O3 and MnO have a similar removal ratios of 81.33% and 82.81%, respectively.

scholarly journals Effects of Blade Parameters on the Flow Field and Classification Performance of the Vertical Roller Mill via Numerical Investigations

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Chang Liu ◽  
Zuobing Chen ◽  
Weili Zhang ◽  
Chenggang Yang ◽  
Ya Mao ◽  
...  
Keyword(s):  
Flow Field ◽  
Pressure Difference ◽  
Continuous Phase ◽  
Classification Performance ◽  
Field Analysis ◽  
Discrete Phase Model ◽  
Roller Mill ◽  
Discrete Phase ◽  
Vertical Roller ◽  
Classification Efficiency

The vertical roller mill is an important crushing and grading screening device widely used in many industries. Its classification efficiency and the pressure difference determine the entire producing capacity and power consumption, respectively, which makes them the two key indicators describing the mill performance. Based on the DPM (Discrete Phase Model) and continuous phase coupling model, the flow field characteristics in the vertical roller mill including the velocity and pressure fields and the discrete phase distributions had been analyzed. The influence of blade parameters like the shape, number, and rotating speed on the flow field and classification performance had also been comprehensively explored. The numerical simulations showed that there are vortices in many zones in the mill and the blades are of great significance to the mill performance. The blade IV not only results in high classification efficiency but also reduces effectively the pressure difference in the separator and also the whole machine. The conclusions of the flow field analysis and the blade effects on the classification efficiency and the pressure difference could guide designing and optimizing the equipment structure and the milling process, which is of great importance to obtain better overall performance of the vertical roller mill.

Unsteady Modeling of Powdered Activated Carbon Deposition on Collection Electrode of a Lab-Scale Electrostatic Precipitator (ESP)

2012 ◽  
Author(s):  
Yasmin Khakpour ◽  
Herek L. Clack
Keyword(s):  
Activated Carbon ◽  
Particle Deposition ◽  
Electrostatic Precipitator ◽  
Activated Carbons ◽  
Collection Efficiency ◽  
Continuous Phase ◽  
Powdered Activated Carbon ◽  
Computational Domain ◽  
Discrete Phase Model ◽  
Discrete Phase

Particulate sampling in the flue gas at the Electrostatic Precipitator (ESP) outlet during injection of powdered activated carbons (PACs) has provided strong anecdotal evidence indicating that injected PACs can penetrate the ESP in significant concentrations. The low resistivity of PAC is consistent with poor collection efficiency in an ESP and lab-scale testing has revealed significantly different collection behavior of PAC in an ESP as compared to fly ash. The present study illustrates the use of a commercial CFD package — FLUENT — to investigate precipitation of powdered activated carbon (PAC) in the presence and absence of electric field. The computational domain is designed to represent a 2-D wire-plate ESP channel. The governing equations include those covering continuous phase transport, electric potential, air ionization, and particle charging. The particles are tracked using a Lagrangian Discrete Phase Model (DPM). In addition, a custom user-defined function (UDF) uses a deforming boundary condition and a prescribed critical particle velocity to account for particle deposition and dust-cake growth on the electrodes. The effect of Electrohydrodynamics (EHD) induced flow on the ESP collection efficiency under various flow and particle characteristics as well as different ESP configurations are illustrated.

Numerical study on the removal and distribution of non-metallic inclusions in electroslag remelting process

2019 ◽  
Vol 135 ◽  
pp. 1300-1311 ◽  
Author(s):  
Xuechi Huang ◽  
Baokuan Li ◽  
Zhongqiu Liu ◽  
Xiao Yang ◽  
Fumitaka Tsukihashi
Keyword(s):  
Numerical Study ◽  
Electroslag Remelting ◽  
Metallic Inclusions

CFD Study on must of Grapes Separation in a Hydrocyclone

2013 ◽  
Vol 837 ◽  
pp. 645-650
Author(s):  
Petru Cârlescu ◽  
Ioan Tenu ◽  
Marius Baetu ◽  
Radu Rosca
Keyword(s):  
Cfd Simulation ◽  
Reynolds Stress Model ◽  
Continuous Phase ◽  
Solid Particles ◽  
Advanced Degree ◽  
Separation And Purification ◽  
Discrete Phase Model ◽  
Flow Rates ◽  
Discrete Phase ◽  
Simulation And Experiment

Abstract. Hydrocyclones are increasingly used in the food industry for various separation and purification. In this paper, an optimization was made to design a hydrocyclone model using CFD (Computational Fluid Dynamics). CFD simulation is performed with FLUENT software by coupling the Reynolds Stress Model (RSM) for must of grapes flow with Discrete Phase Model (DPM) for solid particles trajectory. Coupling of discrete phase (particles) and continuous phase (must of grapes) in the mathematical model is set so that the continuous phase to influence discrete phase. Tracking particles traiectory in this hydrocyclone allows advanced degree is separation so obtained to the maximum particle size approaching the size of a yeast cell 10 μm, without separating them. Hydrocyclone dimensional designed simulation was performed and analyzed on an experimental pilot plant for three different must flow rates supply. Introduced particle flow rates simulation and experiment does not exceed 10% of the must flow rates. The degree of separation obtained is in agreement with experimental data.

Experimental Test for Evaluation of SCC Static Segregation

2014 ◽  
Vol 875-877 ◽  
pp. 68-76 ◽  
Author(s):  
Salah Eddine Bensebti ◽  
Salima Aggoun ◽  
El Hadj Kadri ◽  
Ourdia Haddad
Keyword(s):  
Experimental Test ◽  
Filling Ratio ◽  
Paper Study ◽  
Column Test ◽  
Self Compacting Concrete ◽  
High Quality ◽  
Experimental Assessment ◽  
Slump Flow ◽  
Static Resistance ◽  
French Association

A Self-Compacting Concrete (SCC) is by definition one that, due to its own weight, pours and sets in place in the most complex reinforced moulds. It is important to note that the material must not undergo any form of segregation, whether “dynamic”, i.e. when it occurs during flowing, or “static”, i.e. when it occurs in the mould after compaction of different materials in the concrete. In this paper, study of static resistance segregation of self-compacting concretes is presented. Experimental assessment of segregation is carried out by procedure, which is realized in this paper. This procedure is similar to column test but different cylinder geometry and splitting is carried out at the end of setting. For each of the different mixtures studied, we also measure the slump flow, the filling ratio (L-box test), the screen stability and the V-funnel flowing time. The results obtained show that in the case of SCC, specific tests must be carried out to assess static segregation, especially when slump flow is above 70 cm. This study also shows that it is possible to obtain high quality SCC (with no risk of segregation) with screen stability test values in the region of 30%, which are much greater than the usual 15% recommended pat the French association of civil engineering AFGC [1].

Online Electromagnetic Filtration of Molten Aluminum Using a Multistage Separator System

2015 ◽  
Vol 15 (1) ◽  
pp. 89-92
Author(s):  
Da Shu ◽  
Jun Wang ◽  
Baode Sun
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Field ◽  
Molten Aluminum ◽  
External Electromagnetic Field ◽  
Grain Refiner ◽  
High Quality ◽  
Inclusion Content ◽  
Average Efficiency ◽  
Filtration System ◽  
Metallic Inclusions

AbstractElectromagnetic filtration is a new method for the removal of micro-sized non-metallic inclusions from molten aluminum by means of an external electromagnetic field. This paper introduces a multistage electromagnetic filtration system using alternating magnetic field and its application in semi-continuous casting of aluminum billets. The inclusion content was quantitatively determined through PoDFA sampling and analysis. Results showed that the average efficiency of the removal of inclusion particles and oxide films could reach 93.8% and 80.9%, respectively. The content of inclusion particles without grain refiner could be decreased to a level of 0.02 mm2/kg aluminum, satisfying the requirements in terms of the cleanliness of high-quality aluminum products.

Numerical Simulation of Steam Generator Tube Rupture Sequence in ADS Reactor

2014 ◽  
Author(s):  
Xu Yang ◽  
Tao Zhou ◽  
Daping Lin ◽  
Xiaolu Fang ◽  
Baixu Chen ◽  
...  
Keyword(s):  
Steam Generator ◽  
Continuous Phase ◽  
Discrete Phase Model ◽  
Primary Coolant ◽  
Steam Generator Tube ◽  
Spallation Target ◽  
Steel Material ◽  
Stainless Steel Material ◽  
Discrete Phase ◽  
Secondary Side

In ADS reactor which choose LBE (Lead-Bismuth Eutectic) as coolant and spallation target. While SGTR (Steam Generator Tube Rupture) accident occur, water in secondary side will inject to LBE in primary coolant, and flow with LBE. The code of FLUENT will be used, steam is looked as particle, and standard k-ε model is used to predict turbulence variation of continuous phase in core. The DPM (Discrete Phase Model) will be used to track the trajectory of the particles. The distribution of steam in core will be obtained, which will verify the safety of reactor. The results show that the steam flowing across the core with LBE, might accumulate in some position and cause a surge of power. At the same time, the aggregation of steam at the channel might lead to a steam plug, and hinder the flow of the coolant in core, then core overheating might occur. Last but not least, local accumulation of water vapor may accelerate the corrosion of stainless steel material in core.

Numerical Simulation of Behaviour a Non-Metallic Inclusions in an One-Strand Slab Tundish with Steel Flow Controll Devices

2011 ◽  
Vol 56 (3) ◽  
pp. 611-618 ◽  
Author(s):  
A. Cwudziński
Keyword(s):  
Numerical Simulation ◽  
Liquid Steel ◽  
Flow Reactor ◽  
Control Device ◽  
Discrete Phase Model ◽  
Internal Working ◽  
Working Space ◽  
Metallic Inclusions ◽  
Discrete Phase ◽  
Steel Flow

Numerical Simulation of Behaviour a Non-Metallic Inclusions in an One-Strand Slab Tundish with Steel Flow Controll DevicesAn effective refining of liquid steel can be carried out either in a tundish or in the mould of a CSC machine. Being a flow reactor, the tundish performs the function of a link between the steelmaking ladle and the mould. Owing to this fact, the liquid steel resides in the tundish for a specific time, which enables the tundish to be used for refining purposes. For modification oftundish internal working space, two types of flow control device (FCD), namely a ceramic gas-permeable barrier and a subflux turbulence controller (STC), were proposed. For simulation of movement of gas phase and non-metallic inclusions, a discrete phase model was used. The obtained results unambiguously indicate which of the proposed tundish equipment configurations will be more advantageous for intensifying the process of liquid steel refining from NMIs.

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