Physical and numerical modeling of liquid slag entrainment in mould during slabs casting

2020 ◽  
Vol 117 (5) ◽  
pp. 509
Author(s):  
Marcin Bielnicki ◽  
Jan Jowsa

The paper presents results of physical and numerical modeling of liquid slag entrainment during continuous casting of steel slabs process. The main aim of this work was to determine the critical casting speed and also to specify, which entrainment mechanism is most responsible for transport of slag droplets into steel volume. Physical modeling was based on water-oil model of mould, made on reduced linear scale of Sl = 0.4. In mathematical modeling, Realizable k-ε and LES WALE models were used to describe turbulent motion of water and oil, whereas Volume of Fluid model was used to take into account interactions between phases. It was found, that the main cause of slag entrainment is the formation of von Karman vortex in the vicinity of submerged entry nozzle. The results of laboratory experiments and numerical simulations were compared each other. Both method are a useful tools for modeling of slag entrainment. Great agreement was found between laboratory experiments and numerical simulation carried out using LES WALE model, regarding the shape of the oil and oil entrainment as a result of vortex structures formation. However, in the simulation case using Realizable k-ε model, the oil entrainment hasn’t been modeled for the conditions under consideration.

2008 ◽  
Vol 14 (2) ◽  
pp. 72-87 ◽  
Author(s):  
Koustuv Debnath ◽  
Amartya Kumar Bhattacharya ◽  
Biswanath Mahato ◽  
Agnimitro Chakrabarti

Author(s):  
D. Jaya Krishna

Abstract In the present study, the numerical investigation has been performed for a phase change material (PCM)-based longitudinal fin heat sink. The fins are taken as an integral part of the heat sink and are made up of aluminum. The PCM considered in the study is RT44HC. Heat is transferred to the heat sink through its horizontal base. In order to simulate the melting behavior of the PCM, volume of fluid model has been used. To attain the best configuration with optimum operational time, Taguchi method has been used followed by analysis of melt fraction and maximum base temperature. The optimized heat sink configuration with maximum operational time has been obtained at the critical temperatures of 54.8 °C, 63 °C, and 72.6 °C.


Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1870
Author(s):  
Jorge Badules ◽  
Mariano Vidal ◽  
Antonio Boné ◽  
Emilio Gil ◽  
F. Javier García-Ramos

Agitation inside agricultural sprayer tanks can be studied while using an international standard procedure, based on obtaining internal samples of liquid. However, in practice, this test is not easy to perform. Herein, we propose the explicit study of the mixing procedure with biphasic computer simulations using Computational Fluid Dynamics (CFD). An experimental test was performed on a 3000 L tank of a commercial air-assisted sprayer, with two different agitation system configurations, in order to compare the results of several theoretical physical models of biphasic flows for CFD, both Eulerian and Lagrangian. From the analysis of these theoretical models, we conclude that the Volume of Fluid model is not viable and the Discrete Phase Model produces erroneous results, while the Eulerian and Mixture models can both be useful. However, the results obtained suggest that complex streams generated by real-world agitation systems produce more errors in calculations. Both models can be conducted in the design phase, prior to the implementation of the machine. In addition, the computer simulations allow for researchers to analyse the mixing process in detail, making it possible to evaluate the efficiency of an agitation system according to the time that is required to reach mixture homogeneity.


2015 ◽  
Vol 60 (4) ◽  
pp. 2905-2912 ◽  
Author(s):  
J. Jowsa ◽  
M. Bielnicki ◽  
A. Cwudziński

The behaviour of liquid slag in the mould is one of the key research areas of the continuous steel casting process. Numerical simulations of steel casting in the mould equipped with submerged entry nozzle, intended for slab casting, have been carried out within the study. For modelling the behaviour of the interfaces of the liquid steel - liquid slag - air system, the VOF method was employed. In the conducted simulations, seven different procedures for the discretization of the interface of individual phases were tested. The computation results have revealed that the “entrapment” of fine slag portions into liquid steel occurs in the system under investigation; the cause of this phenomenon is explicated by the Kelvin-Helmholtz theory.


2003 ◽  
Author(s):  
Gerrit Blacquière ◽  
Edith van Veldhuizen

2006 ◽  
Vol 530-531 ◽  
pp. 376-381 ◽  
Author(s):  
Luiz Gustavo Martins Vieira ◽  
João Jorge Ribeiro Damasceno ◽  
Marcos A.S. Barrozo

Hydrocyclones are centrifugal devices employed on the solid-liquid and liquid-liquid separation. The operation and building of these devices are relatively simple, however the flow inside them is totally complex and its prediction is very difficult. The fluid moves on all possible directions (axial, radial and swirl), the effects of turbulence can not negligible and an air core along the center line of the hydrocyclone can appear when the operational conditions are favorable. For that reason, the most models that are used to predict the hydrocyclone performance are empirical and require the collection of the main operational and geometric variables in order to validate them. This work objectified to apply Computational Fluid Dynamics (CFD) on Bradley Hydrocyclone and compare the results from this technique to empirical models. The numerical simulation was made in a computational code called Fluent® that solves the transport equation by finite volume technique. The turbulence was described by Reynolds Stress Model (RSM) and the liquid-gas interface was treated by Volume of Fluid Model (VOF). In agreement with the results from the simulation, it was possible to predict the internal profiles of velocity, pressure, air core, particle trajectories, efficiencies, pressure drop and underflow-to-throughput ratio.


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