Numerical Analysis of Effect of Initial Bubble Size on Captured Bubble Distribution in Steel Continuous Casting Using Euler-Lagrange Approach Considering Bubble Coalescence and Breakup

Abstract

A mathematic model considering the bubble coalescence and breakup using the Euler-Lagrange approach has been developed to study the effect of the initial bubble size on the distribution of bubbles captured by the solidification shell. A hard sphere model was applied for dealing with the bubble collision. Advanced bubble coalescence and breakup models suitable for the continuous casting system and an advanced bubble captured criteria have been identified established with the help of user-defined functions of FLUENT. The predictions of bubble behavior and captured bubble distribution agree with the water model and plant measurements well respectively. The results show that the number of small bubbles captured by solidification shell is much higher than that of large bubbles. What is more, the number of captured bubbles at the sidewalls decreases with the distance from the meniscus. For the case of large gas flow rate (gas flow fraction of 8.2%), the initial size of bubbles has little effect on bubble captured distribution under various casting speeds. When the gas flow rate is small (gas flow fraction of 4.1%), the number density of captured bubbles increases as the initial bubble size increases, and the effect of initial bubbles size on captured bubble number density is amplified when the casting speed decreases. The average captured bubble diameter is about 0.12–0.14 mm. Additionally, for all cases, the initial bubble size hardly affects the average size of captured bubbles.

Numerical Simulation of Flow and Argon Bubble Distribution in a Continuous Casting Slab Mold under Different Argon Injection Modes

“…Figure 3 shows the bubble distribution within the mold at the casting speed of 0.63 m/min and argon flow rate of 0.638 L/min at the SEN. It can be seen that most of the bubbles floated near the SEN, especially the large bubbles, while the small bubbles moved along with the jet flow to the narrow face because of the effect of buoyancy, which is consistent with the flow characteristics calculated by Zhang [21] and Yang [28]. The bubble diameters within the mold obtained by the current model are shown in Figure 3b, which indicates that both the distribution and penetrating depth of argon bubbles agree well with the experiment.…”

Dynamic mode decomposition of magnetohydrodynamic bubble chain flow in a rectangular vessel

“…While single bubble magnetohydrodynamic (MHD) flow is fairly well studied, many aspects of bubble collective dynamics, especially in presence of MF, are not properly understood [17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Aside from preventing optimization and efficiency improvements for industrial processes where the underlying physics are unclear, it is also impossible to significantly improve effective models for bubble flow (Euler-Euler and Lagrangian) without insights into how bubbles interact in MHD flow (or without applied MF) [15,[31][32][33]. Through recent developments, however, fundamental investigation of bubble chain systems mimicking industrially relevant conditions is underway [13,14,[34][35][36][37][38][39].…”

“…Compute the full DMD modes of the system ϕ i = U φi (42) Truncate the modes ϕ i to the first m elements. (Optional) Compute the initial amplitudes of the DMD modes [5] It is important to note that (32) does not have a unique solution. To address this, it is recommended to choose a solution that is closest to K+ and K−1 − as the matrix K is expected to be close to these matrices.…”

Measurement and Analysis of Bubble Size Distribution in the Electrochemical Stirred Tank Reactor

“…Large bubbles prefer to escape quickly at the top surface, whereas tiny bubbles are more likely to reach the side wall and mold depth. Also, tiny bubbles increase the gas-liquid interface area, the contact time between the air bubble and the water rises, and the mass transfer process and flow behavior change [10,11]. For optimizing bubble reactor processes, knowing the BSD in the specific system under various operating conditions is crucial.…”