Effect of Mold Width on the Flow Field in a Slab Continuous-Casting Mold with High-Temperature Velocity Measurement and Numerical Simulation

In this paper, the effects of the width of the mold on the surface velocity, flow field pattern, turbulent kinetic energy distribution, and surface-level fluctuation in the mold were studied with measurement of the flow velocity near the surface of the mold at high temperature with the rod deflection method and numerical calculation with the standard k-ε model coupled with the discrete-phase model (DPM) model for automobile exposed panel production. Under the conditions of low fixed steel throughput of 2.2 ton/min, a nozzle immersion depth of 140 mm, and an argon gas flow rate of 4 L/min, as the width of the mold increases from 880 mm to 1050 mm and 1300 mm, the flow velocity near the surface of the mold decreases. The flow direction changes from the positive velocity with the mold widths of 880 mm and 1050 mm to the unstable velocity with the mold width of 1300 mm. The calculated results are in good agreement with the measured results. The turbulent kinetic energy near the submerged entry nozzle (SEN) gradually increases, and the risk of slag entrainment increases. Under the conditions of high fixed steel throughput of 3.5 ton/min, the SEN immersion depth of 160 mm, and the argon gas flow rate of 10 L/min, as the width of the mold increases from 1600 mm to 1800 mm and 2000 mm, the velocity near the mold surface decreases. The flow velocity at 1/4 of the surface of the mold is positive with the mold width of 1600 mm, while the velocities are negative with the widths of 1800 mm and 2000 mm. The calculated results are basically consistent with the measured results. The high turbulent kinetic energy area near the nozzle expands to a narrow wall, and the risk of slag entrainment is significantly increased. In both cases of low and high fixed steel throughput, the change rules of the flow field in the mold with the width are basically the same. The argon gas flow rate and the immersion depth of SEN should be adjusted reasonably to optimize the flow field in the mold with different widths under the same fixed steel throughput in the practical production.

Analysis of Free Vibration Characteristics of Cylindrical Shells with Finite Submerged Depth Based on Energy Variational Principle

Based on the principle of energy variation, a calculation model for the free vibration characteristics of a cylindrical shell with a finite submerged depth considering the influence of the free liquid surface is established in this paper. First, the Euler beam function is used instead of the shell axial displacement function to obtain the shell kinetic energy and potential energy. Then, by using the mirror image method, the analytical expression of the fluid velocity potential considering the free surface is obtained, and the flow field is added to the system energy functional in the form of fluid work. Then the energy functional is changed to obtain the shell–liquid coupled vibration equation. Solving the equation can obtain the natural frequencies and modes of the structure. The comparison with the finite element calculation results verifies the accuracy of the calculation model in this paper. The research on the influence of the free liquid surface shows that compared to the infinite domain, the free liquid surface destroys the symmetry of the entire system, resulting in a difference in the natural frequency of the positive and negative modes of the shell, and the circumferential mode shapes are no longer mutually uncoupled trigonometric functions. The existence of free liquid surface will also increase the natural frequency of the same order mode, and the closer to the free surface, the natural frequency is greater. As the immersion depth increases, the free vibration characteristics will quickly tend to the result of infinite domain. Additionally, when the immersion depth is equal to or greater than four times the radius of the shell structure, it can be considered that the free liquid surface has no effect. These law and phenomena have also been explained from the mechanism. The method in this paper provides a new analytical solution pattern for solving this type of problem.

Effects of Impeller Rotational Speed and Immersion Depth on Flow Pattern, Mixing and Interface Characteristics for Kanbara Reactors using VOF-SMM Simulations

The Kanbara Reactor (KR) is a primary desulfurization technology in the hot metal pretreatment refining process that is widely employed in the modern steelmaking industry. The operating parameters of KR impeller immersion depth (IID) and rotation speed (IRS) have a crucial impact on the process performance and the desulfurization effect. Still, their influences have not been fully understood. This study systematically investigated the effects of IID and IRS on the flow pattern, mixing behavior, vortex core depth, and free surface characteristics for KR processes based on a 3D Volume of Fluid (VOF) model coupled with the sliding mesh method (SMM). The model was validated via scale-down water model experiments and then applied to the KR process, and simulations found that IID and IRS have different impacts on the flow pattern. Specifically, the discharge flow location moves downward with IID increasing, but the discharge strength and mean velocity hardly changes. Comparatively, the rise of IRS significantly increases the mean velocity, but few changes occur to the discharge flow position. Increasing IRS improves bath hydrodynamics, strengthens recirculation, and efficiently shortens mixing time, but IID has a neglectable effect on these features. The minimum mixing time is 55 s at a maximum IRS of 260 rpm. Moreover, the vortex core depth and free surface velocity visibly increase with the increase of IRS. Comparatively, IID has a limited effect on the flow and mixing behavior but directly impacts the distribution of recirculation regions at the axial direction and the velocity gradient on the free surface at the radial direction. Furthermore, the correlation equations of these critical parameters as a function of the operating parameters were obtained. The results from this study may provide references for operating optimizations and industrial practices of KRs.

Effect of SEN immersion depth on mold flow profile and slag entrapment during continuous casting of steel

Mold flux entrapment during continuous casting of steel contributes to both surface and sub-surface defects in the final product. Continuous casting operating parameters such as casting speed, SEN immersion depth, SEN port geometry, argon flow, and mold EMS significantly affect the mold flow conditions and flow profile. During continuous casting operation, SEN immersion depth is continuously varied to avoid localized erosion of SEN, and it impacts the flow dynamics in the mold. In the present work, water modeling studies were carried out for a wide range of mold widths (1200-1800 mm) and casting speeds (0.8-1.4 m/min) on a 0.5 scaled down water model to optimize casting speed for different combinations of SEN immersion depth and mold width. Results from water modeling were further validated using nail board studies in the actual plant. A safe operating matrix was identified from these experiments to avoid mold slag entrapment during continuous casting.

The Sufi Experience in Mahmoud Darwish's Poetry- the Hoopoe poem as a model: التجربة الصوفية في شعر محمود درويش- قصيدة الهدهد أنموذجًا

This study is based on the analysis of the influence of Sufi thought on the poet Mahmoud Darwish in the poem "Hoopoe", which is combined with the book of Farid al- Din al- Attar "The Logic of the Bird." It turns out that Darwish turned to the world of brightness in order to take advantage of the mystical terminology of immersion, depth in the image, and difficulty in coding. In fact, his textual relevance in this experiment is not limited to his crucible in the crucible of "bird logic" alone, but extends to all sources of Persian mysticism, and therefore the researcher sought to reveal the references between the "bird logic" and the foundations of Sufi thought, and then monitor their reflections, taking into account Consider that the issue of belonging to the land or shifting from it is one of the most serious issues in the process of Mahmoud Darwish, and the reason is the stark contrast between his revolutionary and Sufi tolerant thought.

EFFICIENCY OF THE SUBMERSIBLE COMBUSTION DEVICE GORENJE

Получены динамические характеристики производительности аппарата погружного горения от средних характеристик потока смеси и переменной глубине погружения горелки. The dynamic characteristics of the performance of the submersible combustion device are obtained from the average characteristics of the mixture flow and the variable immersion depth of gorenje.

EFFICIENCY OF FOAM WASTEWATER DISPOSAL

Получены динамические характеристики производительности пеногенератора от времени в сточной воде при различных концентрациях некаля, являющегося поверхностно-активным веществом, и переменной глубине погружения сопла. The dynamic characteristics of the foam generator performance as a function of time in the waste water at different concentrations of non-crystal, which is a surfactant, and variable nozzle immersion depth are obtained.