Mathematical simulation and physical modeling of unsteady fluid flows in a water model of a slab mold

Abstract

Fluid flow of water in a model of a slab caster has been simulated using the large eddy simulation (LES) computational approach, and the simulated results are compared with experimental measurements performed using digital particle image velocimetry (DPIV) techniques. Simulation results agree acceptably well with the experimental measurements of instantaneous velocity fields. Flow patterns change with time as a consequence of the vertical oscillation of the jet core. These oscillations are originated by the residual Reynolds stresses that characterize turbulent flows. The asymmetry of fluid flows caused by these stresses provides biased flows. Thus, turbulence originates natural biasing effects without the influence of other operating factors such as the slide gate opening, gas bubbling, or inclusions clogging of the submerged entry nozzle (SEN). Instantaneous velocities follow periodical behaviors with time whose frequencies increase with increases of flow rate of liquid. Periodical flow changes originate velocity spikes, at some given casting speed, which are physically and mathematically identified. These sudden changes of fluid velocities are responsible of unsteady phenomena associated with fluid dynamics during steady operations of the mold.

Transient Thermo-fluid and Solidification Behaviors in Continuous Casting Mold: Evolution Phenomena

“…Mathematical simulations and physical experiments have been developed and applied to study the flow patterns and the velocity fields in the mold region. [6][7][8] Banderas et al 9) characterized the periodical behavior of turbulent flows using the large eddy simulation (LES) computational approach, which compared with the Digital Particle Image Velocimetry (DPIV) measurement. A similar model by Lopez et al 10) included the effects of casting speed on fluid-flow structure, meniscus topography and kinetic energy distri- bution.…”

Instability and Periodicity of Asymmetrical Flow in a Funnel Thin Slab Continuous Casting Mold

“…The cassette filter function 23) was used in this work, G(x, x′) can be expressed as: (2) where V = ΔxΔyΔz is the volume of a computational cell.…”

“…2, obtained from the k-ε model, the predicted flow pattern inside the present calculation mold was symmetric and stable, failure to explain the asymmetrical and oscillating fluid flow inside the mold. In recent studies, 8,10,22,23) the large eddy simulation (LES) has been successfully applied to obtain the transient asymmetrical flow inside the mold. Yuan et al 22) combined LES and particle image velocimetry (PIV) measurements in a scaled water model, finding good agreement between both types of data.…”

“…The asymmetric flow was found between the two rolls in the lower recirculation region, which was important for the inclusion motion and bubble entrapment. RamosBanderas et al 23) studied the fluid flow of water in a slab mold using LES and PIV, founding the asymmetrical flow and the flow pattern changed with time as a consequence of the vertical oscillation of the jet core. Recently, authors developed different LES models for the single phase (molten steel) flow 8) and the two-phase (molten steel and argon gas) flow 10) inside the slab mold, respectively.…”

Instability of Fluid Flow and Level Fluctuation in Continuous Thin Slab Casting Mould

“…Honeyands pointed out that the interaction between the confined jets and the recirculating fluid eddies could be a critical factor responsible for the oscillation in the thin slab flow system. Ramos-Banderas et al 6) studied the fluid flow of water in the slab mould using Digital Particle Image Velocimetry (DPIV) and found that the asymmetry of fluid flows and the flow pattern changed with time as a consequence of the vertical oscillation of the jet core. The jet angle and its impinging position on the mould narrow face varied with time corroborating the oscillatory motion of the entry jet.…”