Simulation of special flow affecting dross formation on steel strip in galvanising bath

Abstract

The zinc flow in a galvanising bath is numerically simulated for three cases, and the flow field is analysed using three-dimensional views. It is found that the flow near the zinc surface directs from the strip to the ingot side when inductors are equipped and whether ingots are melting or not, and the flow direction is opposite to that near the zinc surface for the case without inductor and ingot, which does not exist during the bath operation process. Whirlpools are found to be formed between the snout and the bath side walls, which will increase the chance of dross particles touching the strip surface. Some effective measures are proposed to stop more dross from adhering to strip. This work will lay foundation for the optimisation of the galvanising process to improve the coating quality of steel strip.

Size Effect on Flow Field and Dynamic Deposition of Bottom Dross in a Molten Zinc Pot

“…8) Steel strip width, speed, and bath configuration can influence the flow field of the Al-Zn liquid and alloy component, as well as the dross formation, distribution and coating quality of the steel strip. 9,10) Physical and numerical models are usually used to understand the flow characteristics in the process of hot-dip galvanizing bath. [11][12][13][14] The simulations were commonly carried out by the computational fluid dynamics software using a model of mass and momentum with the k-ε turbulence model.…”

Numerical Simulation of Zinc Flow in Different Layouts of Galvanization Pot

“…d) The finite volume numerical method used the SIMPLE 10,11 algorithm to solve the equations performed; e) The selection method was based on the methods most commonly used in publications 10,11 , the pressure was discretized with the standard scheme, while momentum, turbulent kinetic energy, turbulent dissipation rate and equations of energy are discretized with the first-order upwind scheme 11,12,13 ; f) The convergence criteria for calculations of momentum, velocities, turbulence and dissipation of turbulence energy were the results of the residuals for calculating interactions less than 1x10 -5 . The following conditions were used for the simulation according to Table 1 The strip was divided into 4 regions, Figure 2, to better map the amount of top-dross particles carried to each region of the strip by the flow of zinc, in Figure 2 the stabilizer and deflector rollers that are submerged in the zinc bath, there is still the snout region and the submerged rolls.…”

Trajectory of Top-Dross Particles During the Melting of Zinc Ingot in Galvanizing Pot

“…Where σ k =1.0, σ ε =1.3, Cε1=1.44, Cε2=1.92, P is defined as the shear production and G is the effect of buoyancy on the production of turbulence 16,17. The numerical method of finite volumes used the SIMPLE algorithm 16,17 as the solution of the relevant equations. The choice of the discretization method was based on the methods most used in publications 16,17. Pressure was discretized with the standard scheme, while momentum, turbulent kinetic energy, turbulent dissipation rate and energy equations are discretized with the first-order upwind scheme 16,17,18 .…”