Numerical Simulation of Tracers Transport Process in Water Model of a Vacuum Refining Unit: Single Snorkel Refining Furnace

Abstract

The improvement of mixing conditions in vacuum refining unit plays an important role in enhancing the purity and decarburization of molten steel. A numerical simulation is established to calculate the transport and mixing process of tracers in a water model of Single‐Snorkel Refining Furnace. The results show that the transport process of tracer in water model consists of one main circulation stream (inside the ladle and the vacuum chamber) and two side circulation streams (inside the ladle). The injection of KCl tracer can enhance the downward stream velocity and the stream deviates to the axial center of the ladle. After a while (about 30 s), the downward stream gradually returns to the state when the tracer is not injected. The difference between the transport process of pure water tracer and KCl solution tracer is that the KCl solution tracer flows downward at a higher pace from the vacuum chamber to the bottom of the ladle and later disperses rapidly from the bottom to the nozzle‐located side wall of the ladle. The upward transport process of KCl tracer is slowed down due to the existence of “dead zone” at the bottom of the nozzle‐located side wall of the ladle.

Turbulent flow with nonequilibrium chemical reaction in single snorkel RH

“…Drag force coefficient ( C D ) is determined by the Schiller–Naumann drag model (Kim et al , 2007; Ling and Zhang, 2019): with bubble Reynolds number (Re) (Kishan and Dash, 2006; Zhang et al , 2020): …”

“…2.1 Co-Ar-molten steel flow Due to the complicated metallurgical phenomena, several assumptions in Table 1 are introduced to reduce the exceedingly heavy computational load (Thomas and Zhang, 2001;Ajmani et al, 2004;Wei and Hu, 2005;Yang et al, 2012;Dai et al, 2020;Zhang et al, 2020). The CO-Ar-molten steel flow can be described by following governing equations: Mixture density (r m ):…”

“…Single snorkel RH (SSRH) developed from traditional RH (Rheinstahl–Heraeus) has been used to produce ultra-low carbon steel since 1970s (Zhang et al , 2020). Figure 1(a) shows that molten steel circulates among ladle, snorkel and vacuum chamber.…”

On the Ladle Shroud Design and Mis-alignment Effects on the Fluid Flow in a Metallurgical Tundish- A CFD Model Study

“…The Realizable Two-Layer k-ε model, which combines the realizable k-ε model [20] with the two-layer approach proposed by Rodi [21] , is applied to calculate the turbulent flow in tundish. The formula are not reproduced here and can be found in reference [22] . The volume mesh is generated in STAR CCM+, utilizing the trimmer and prism layer meshing options.…”

Water Modeling on Circulating Flow and Mixing Time in a Ruhrstahl–Heraeus Vacuum Degasser

“…The tracer was added from the feed inlet port on the vacuum chamber sidewall, and the mixing time was defined as the first time when the conductivity stabilized at AE5%, [21,36] AE3%, [37] or AE1%. [38] As the mixing time is related to the location of monitors and the fluid flow field distribution in the ladle, [6] many researchers have given out the mixing time of several points for different positions and various operation conditions. [23,39,40] However, it is difficult to figure out the mixing time distribution on the whole vertical center section in the ladle.…”