scholarly journals 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

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1160
Author(s):  
Weidong Yang ◽  
Zhiguo Luo ◽  
Nannan Zhao ◽  
Zongshu Zou
Keyword(s):  
Continuous Casting ◽  
Flow Rate ◽  
Bubble Size ◽  
Gas Flow ◽  
Bubble Coalescence ◽  
Water Model ◽  
Number Density ◽  
Gas Flow Rate ◽  
Bubble Distribution ◽  
Lagrange Approach

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.

Flow Field and Gas-Bubble Size Analysis in Water Model for the Process of Aluminum Melt Degassing by Particle Image Velocimetry

2007 ◽  
Vol 546-549 ◽  
pp. 1087-1092 ◽  
Author(s):  
Rui Zhi Wu ◽  
Da Shu ◽  
Jun Wang ◽  
Bao De Sun ◽  
Mi Lin Zhang
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Bubble Size ◽  
Gas Flow ◽  
Water Model ◽  
Size Analysis ◽  
Gas Bubble ◽  
Gas Flow Rate ◽  
Aluminum Melt ◽  
Rotary Speed

The flow field and gas-bubble size during the process of aluminum melt degassing were investigated in water model. A Φ400mm×400mm transparent water model and an impellor degassing device were used in this study. The instantaneous velocity fields of water and bubbles under the mixture of rotary injector were measured with PIV velocity field measurement technique. Then the pictures of bubbles gained from PIV were analyzed with software to get the bubble size distribution. The results showed that bubble flow field and bubble size were influenced by rotary speed of rotor and gas flow-rate. With the increase of rotary speed of rotor, the horizontal velocity components of bubbles became larger, the stagnant time of bubbles in water increaseed correspondingly and bubble size became smaller. With the increase of gas flow-rate, the longitudinal velocity components of bubbles became larger, the stagnant time of bubbles in water decreased correspondingly, and the bubble size became larger also.

scholarly journals Designing key parameters of bubble plumes to restore water quality by using conceptual models: a case study in a sub-deep reservoir

2020 ◽  
Vol 20 (7) ◽  
pp. 2915-2927
Author(s):  
Chen Lan ◽  
Jingan Chen ◽  
Jianyang Guo ◽  
Jingfu Wang
Keyword(s):  
Flow Rate ◽  
Bubble Size ◽  
Gas Flow ◽  
Bubble Radius ◽  
Bubble Plume ◽  
Gas Flow Rate ◽  
Empirical Formulas ◽  
Bubble Plumes ◽  
Deep Reservoir ◽  
First Time

Abstract Bubble plumes are a popular hypolimnetic reaeration technique in deep-water reservoirs since they have the advantage of delivering direct reaeration to the hypolimnion. Improving the understanding of the integrated reaeration processes is beneficial to optimize the reaeration capacity of the aeration or oxygenation system. In this study, the discrete bubble model was first employed to design an oxygenation system for a sub-deep reservoir (the Aha Reservoir, southwest China, with water depths of 10–30 m). A new approach involving the discrete bubble model was used to determine the initial bubble size of the bubble plume applied. The intrusion models were demonstrated to be useful for designing the gas flow rate of the reaeration system. Using the intrusion models, we predicted the intrusion thickness and intrusion distance during operation for the first time. Subsequently, we verified the predictions and produced more realistic empirical formulas. At present, reports about recommendations on initial bubble size and gas flow rate are rare, and practical verification is absent. Taking the Aha Reservoir as an example, the initial bubble radius of 1 mm and the gas flow rate of 20 m3·h−1 were recommended for bubble plume oxygenation and were found to be successful in the field. Our understanding of the reaeration processes during the operation of the bubble plume system is far from comprehensive, but this study serves to highlight the potential of the discrete bubble model and the intrusion models for designing a bubble plume system in an individual lake.

scholarly journals Evaluation of Critical Gas Flow Rate for the Entrapment of Slag Using a Water Model.

1994 ◽  
Vol 34 (2) ◽  
pp. 164-170 ◽  
Author(s):  
Manabu Iguchi ◽  
Yutaka Sumida ◽  
Ryusuke Okada ◽  
Zen-ichiro Morita
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Water Model ◽  
Gas Flow Rate

Effect of Gas Injection with Multi-hole Orifices on Bubble Behavior during Metal Refining

2011 ◽  
Vol 233-235 ◽  
pp. 1940-1945
Author(s):  
Fang Jiang ◽  
Guo Guang Cheng ◽  
Hai Kuo Yang
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Radial Direction ◽  
Gas Injection ◽  
Hole Diameter ◽  
Bubble Coalescence ◽  
Gas Flow Rate ◽  
Bubble Behavior ◽  
Cold Model ◽  
Optimal Distance

Cold model experiments have been conducted to make clear the effect of orifices on bubble behavior based on the comparison of 1-hole and 4-hole configurations. It is found that this effect is closely related to the gas flow rate and the orifice configuration. For 1-hole orifices, bubble behavior is influenced by the hole diameter at low gas flow rate. Nevertheless, in the region of high gas flow rate, this effect becomes less obvious. However, bubble behavior is strongly affected even at high gas flow rate when 4-hole orifices are used. It is also shown there exists an optimal distance between holes for 4-hole orifices. Below this value, the hole distance is too small to adequately avoid bubble coalescence in the radial direction. Above this value, little further contribution to avoidance of bubble coalescence can be made, but weight and cost of the orifices will increase.

Inclusion Removal at the Free Surface of Steel Bath by Bubble Flotation

2011 ◽  
Vol 399-401 ◽  
pp. 216-222
Author(s):  
Fang Jiang ◽  
Guo Guang Cheng
Keyword(s):  
Free Surface ◽  
Flow Rate ◽  
Bubble Size ◽  
Gas Flow ◽  
Equilibrium Concentration ◽  
Particle Removal ◽  
Gas Flow Rate ◽  
Inclusion Removal ◽  
Particle Layer ◽  
Polyethylene Particles

In the present work, physical model experiments were carried out to clarify the inclusion removal at the free surface of steel bath. Polyethylene particles were used to simulate the non-wetting inclusions like alumina and silica. The influence of gas flow rate and bubble size on the inclusion removal at the free surface was evaluated. It is demonstrated that not all particles are removed when they arrive at the free surface of liquid bath, and those which are not removed will get back to the bath. It is found an annular particle layer is formed by the removed particles at free surface, which can capture other particles arriving at the free surface. However, the attachment of particles to the annular particle layer is not stable, and re-entrainment of particles occurs at high gas flow rate. It is shown the overall particle removal is determined by a balance of removal and re-entrainment. The particle removal constant increases with the increase in the gas flow rate, but decreases with the increase in bubble size. The equilibrium concentration of particles increases with the increase in gas flow rate and bubble size.

Effect of Bubble Size and Angle of Tapered Upriser Pipe on the Effectiveness of a Two Phase Lifting Pump

2009 ◽  
Author(s):  
P. Hanafizadeh ◽  
M. H. Saidi ◽  
A. Zamiri ◽  
A. Karimi
Keyword(s):  
Gas Phase ◽  
Flow Rate ◽  
Bubble Size ◽  
Gas Flow ◽  
Bubble Diameter ◽  
Design Parameters ◽  
Two Phase ◽  
Bubble Distribution ◽  
Improved Performance ◽  
Different Diameters

Two phase lifting pumps are devices with the ability of lifting liquid phase by injecting the gas phase. Parameters which affect the performance of these pumps are divided into two groups. The first group contains design parameters such as diameter of the pipe, tapering angle of the upriser pipe and the submergence ratio which is the ratio of immersed length to the total length of the upriser. The second group includes operating parameters, such as the gas flow rate, bubble diameter, bubble distribution and inlet gas pressure. In this research, the performance of two phase lifting pump is investigated numerically for different submergence ratios and different diameter of the upriser pipe. For this purpose the two phase pump with a riser length of 914 mm and different diameters (6, 8 and 10 mm), and seven tapering angles (0°, 0.25°, 0.5°, 1°, 1.5°, 2° and 3°) are numerically modeled and analyzed. Different submergence ratios are used, namely: 0.4, 0.6 and 0.8. The numerical results are compared with the existing experimental data in the literature showing a reasonable agreement. The results indicate that decrease in size of the bubble diameter increases mass flow rate of liquid at constant submergence ratios. The present study reports the improved performance of this pump with decrease in bubble size and increase in angle of tapered upriser pipe. Moreover, the results show that the tapered upriser pipe with 3° tapering angle gives the highest efficiency at nearly all submergence ratios. Further, the highest efficiency of the pump is shown to be at the largest submergence ratio, namely 0.8.

scholarly journals An Experimental and Simulated Study on Gas-Liquid Flow and Mixing Behavior in an ISASMELT Furnace

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 565 ◽  
Author(s):  
Hongliang Zhao ◽  
Tingting Lu ◽  
Pan Yin ◽  
Liangzhao Mu ◽  
Fengqin Liu
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Turbulent Viscosity ◽  
Mixing Time ◽  
Water Model ◽  
Mixing Efficiency ◽  
Gas Flow Rate ◽  
Factors Affecting ◽  
Sufficient Energy ◽  
Gas Liquid Flow

In this study, a water-model experiment and numerical simulation were carried out in a pilot ISASMELT furnace to study the factors affecting mixing time. The experimental results were compared to the simulation results to test the accuracy of the latter. To study the internal factors that affect the mixing time, the turbulent viscosity and flow field were calculated using simulation. In addition, following previous research, external factors that influence the mixing time including the depth of the submerged lance, lance diameter, gas flow rate, and the presence of a swirler were studied to investigate their effect on the flow regime. The results indicated that the mixing time is controlled by the turbulent viscosity and velocity vector. In addition, it was found that the lance diameter should not exceed 3.55 cm to maintain sufficient energy for stirring the bath. Finally, the optimal gas flow rate that offers the best mixing efficiency was found to be 50 Nm3/h.

scholarly journals Modeling of the Effect of the Gas Flow Rate on the Fluid Flow and Open‐Eye Formation in a Water Model of a Steelmaking Ladle

2018 ◽  
Vol 90 (2) ◽  
pp. 1800365 ◽  
Author(s):  
Eshwar Kumar Ramasetti ◽  
Ville‐Valtteri Visuri ◽  
Petri Sulasalmi ◽  
Riku Mattila ◽  
Timo Fabritius
Keyword(s):  
Fluid Flow ◽  
Flow Rate ◽  
Gas Flow ◽  
Water Model ◽  
Gas Flow Rate ◽  
Eye Formation

Bubble Generation From an Orifice in Upward and Downward Liquid Flow

2013 ◽  
Author(s):  
O. N. Kashinsky ◽  
P. D. Lobanov ◽  
A. V. Chinak ◽  
M. A. Vorobyev
Keyword(s):  
Cross Section ◽  
Flow Rate ◽  
Liquid Flow ◽  
Bubble Size ◽  
Gas Flow ◽  
Liquid Velocity ◽  
Bubble Diameter ◽  
Gas Flow Rate ◽  
Bubble Generation ◽  
Bubble Detachment

The dependencies of detachment bubble diameter on liquid velocity and gas flow rate through a capillary placed in the liquid flow in a channel with cross section of 10×10 mm were obtained. An estimate of bubble detachment frequency was made. The effect of bubble detachment regime on the distribution of bubble size in the flow is discussed.

Sign in / Sign up

Export Citation Format

Share Document