scholarly journals Numerical Simulation of Air Bubble Characteristics in Stationary Water

2007 ◽  
pp. 376-376
Author(s):  
C. X. Zhang ◽  
Y. X. Wang
Keyword(s):  
Numerical Simulation ◽  
Air Bubble ◽  
Bubble Characteristics

scholarly journals Development of Bubble Characteristics on Chute Spillway Bottom

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1129
Author(s):  
Ruidi Bai ◽  
Chang Liu ◽  
Bingyang Feng ◽  
Shanjun Liu ◽  
Faxing Zhang
Keyword(s):  
Size Distribution ◽  
Bubble Size ◽  
Dissipation Rate ◽  
Bubble Diameter ◽  
Bubble Size Distribution ◽  
Impact Zone ◽  
Air Bubble ◽  
Air Supply ◽  
Bubble Characteristics ◽  
The Impact

Chute aerators introduce a large air discharge through air supply ducts to prevent cavitation erosion on spillways. There is not much information on the microcosmic air bubble characteristics near the chute bottom. This study was focused on examining the bottom air-water flow properties by performing a series of model tests that eliminated the upper aeration and illustrated the potential for bubble variation processes on the chute bottom. In comparison with the strong air detrainment in the impact zone, the bottom air bubble frequency decreased slightly. Observations showed that range of probability of the bubble chord length tended to decrease sharply in the impact zone and by a lesser extent in the equilibrium zone. A distinct mechanism to control the bubble size distribution, depending on bubble diameter, was proposed. For bubbles larger than about 1–2 mm, the bubble size distribution followed a—5/3 power-law scaling with diameter. Using the relationship between the local dissipation rate and bubble size, the bottom dissipation rate was found to increase along the chute bottom, and the corresponding Hinze scale showed a good agreement with the observations.

Prediction of Oxygen Transfer Rates from Simple Measurements of Bubble Characteristics

1991 ◽  
Vol 23 (10-12) ◽  
pp. 1941-1950 ◽  
Author(s):  
H. J. Pöpel ◽  
M. Wagner
Keyword(s):  
Oxygen Transfer ◽  
Transfer Rate ◽  
Tap Water ◽  
Oxygen Transfer Rate ◽  
Absorption Method ◽  
Air Bubble ◽  
Air Content ◽  
Lower Accuracy ◽  
Potential Improvement ◽  
Bubble Characteristics

The oxygen transfer rate (OTR) in tap water is generally determined by the instationary absorption method, a precise but rather time consuming and tedious method. Moreover, large quantities of sodium sulfite and water are used in practice when testing aeration equipment in larger tanks. Therefore, a model is proposed by which the oxygen transfer rate can be calculated on the basis of simple and rapid measurements of the air bubble size and its distribution and of the total air content in the water applying a recently developed technique. The accuracy of this method is checked by the absorption method and can be rated as reasonable (0 to 13 % deviation). Greater accuracy is obtained at smaller bubbles (<3 mm) and improvements in this respect are proposed. The proposed method of calculating the OTR from air bubble measurements is considered as a potential improvement of the usual absorption method. Due to its still lower accuracy it can be used at present only in conjunction with the latter method, reducing its chemical and water consumption.

Numerical Simulation Study on the Wave Dissipating Performance of Air Bubbles Breakwater with Double Air Discharged Pipes

2014 ◽  
Vol 501-504 ◽  
pp. 2112-2115
Author(s):  
Cheng Xing Zhang
Keyword(s):  
Numerical Simulation ◽  
Simulation Study ◽  
Numerical Models ◽  
Variable Density ◽  
Air Bubbles ◽  
Two Phase ◽  
Air Bubble ◽  
The Impact ◽  
Phase Fluid

The numerical simulation of air bubbles breakwater was presented in this paper. The two-phase fluid of water and air was assumed as a variable density fluid. The numerical models were developed by FLUENT in order to explore the air amount scale in the system of air bubbles breakwater . The impact of double air discharged pipes on the wave dissipating performance of air bubble breakwater was obtained, which illuminated that under the condition of equal total air amount of Qp, the wave dissipating performance of air bubbles breakwater with double air discharged pipes breakwater may not be improved in comparison with the air bubbles breakwater with single air discharged pipe.

Numerical Simulation Study on the Submerged Pipe Depth of Air Bubbles Breakwater

2013 ◽  
Vol 353-356 ◽  
pp. 2732-2735
Author(s):  
Cheng Xing Zhang
Keyword(s):  
Numerical Simulation ◽  
Simulation Study ◽  
Incident Wave ◽  
Numerical Models ◽  
Variable Density ◽  
Air Bubbles ◽  
Two Phase ◽  
Air Bubble ◽  
The Impact ◽  
Phase Fluid

The numerical simulation of air bubbles breakwater was presented in this paper. The two-phase fluid of water and air was assumed as a variable density fluid. The numerical models were developed by FLUENT in order to explore the air amount scale in the system of air bubbles breakwater . The impact of submerged pipe depth on the wave dissipating performance of air bubble breakwater was obtained, which illuminated that The submerged pipe depth D is deeper, the wave dissipating performance of air bubbles breakwater is better. Furthermore, the effect of air amount and the incident wave periods on the performance of the air bubbles breakwater was analyzed.

Laser-Induced Thermal Bubble-Mixing on a Microfluidic Platform for Lab-on-a-Chip Applications

2012 ◽  
Vol 557-559 ◽  
pp. 2197-2201 ◽  
Author(s):  
Xuan Xuan Dong ◽  
Lei Zhang ◽  
Jian Fu
Keyword(s):  
Numerical Simulation ◽  
Laminar Flow ◽  
Chemical Analysis ◽  
Lab On A Chip ◽  
Multimode Interference ◽  
Air Bubbles ◽  
Interference Effects ◽  
Microfluidic Platform ◽  
Air Bubble ◽  
Nano Fiber

This paper discusses the study of the multimode evolution of microfiber taper and its potential application of micromixer in the lab-on-a-chip. By using numerical simulation, multimode interference effects are demonstrated in the taper transition of a micro-nano fiber. Due to the leaked optical energy gasifies the solution surrounding the taper and produces air bubbles, the laminar flow effect is destroyed with the help of disturbance of air bubble and two solutions are mixed quickly. Therefore, it will be used in microfluidic platform for chemical analysis & testing, chemical synthesis and environmental monitoring.

A Numerical Simulation on Effects of Distance Between Bubble and the Wall on Behavior of Rising Bubble

2013 ◽  
Author(s):  
Ying Huang ◽  
Puzhen Gao
Keyword(s):  
Numerical Simulation ◽  
Vertical Channel ◽  
Narrow Channel ◽  
Horizontal Position ◽  
Two Dimensional ◽  
Volume Of Fluid Method ◽  
Air Bubble ◽  
Rising Bubble ◽  
Water Based ◽  
Different Diameters

A numerical investigation of two-dimensional air bubble behaviors under the effect of gravity in still water based on the VOF (Volume-Of-Fluid) method is carried out. Initially, the surface tension effects on the behavior of the bubble is analyzed, which contains the simulation of the ascending motion of a single air bubble in liquid and the study of the interaction between bubbles in terms of coalescence. Additionally, the differences of single bubble’s rising motion in an infinite surroundings and in a vertical narrow channel are analyzed. The coalescence of bubbles is also studied. The motion of bubbles with different diameters in a vertical channel is simulated. It is found that the bubbles’ behavior depends on the distance between the bubble and the wall. Finally, numerical simulation of the motion of several bubbles of the same size, at the same initial horizontal position and with uniform distribution is carried out. The result reveals that the bubbles at different distances from the wall have different velocities, after a while, the bubbles distribution presents as “U”.

scholarly journals Visualization on Air Bubble Characteristics of the Surf Zone Breaking Waves

2007 ◽  
Vol 54 ◽  
pp. 56-60
Author(s):  
Hiroaki KASHIMA ◽  
Nobuhito MORI ◽  
Natsuki MIZUTANI
Keyword(s):  
Surf Zone ◽  
Breaking Waves ◽  
Air Bubble ◽  
Bubble Characteristics

scholarly journals A modification of level set re-initialized method for the shock waves through the air bubble

2014 ◽  
Vol 18 (5) ◽  
pp. 1525-1530
Author(s):  
Li Zhang ◽  
Jian-Guo Ning ◽  
Tao Zhang
Keyword(s):  
Numerical Simulation ◽  
Shock Waves ◽  
Level Set Method ◽  
Level Set ◽  
Numerical Results ◽  
Smoothing Parameter ◽  
Implicit Method ◽  
Improved Method ◽  
Air Bubble

For the re-initialization problem of the level set method, a new re-initialization formula of smoothing parameter based on the traditional implicit method is proposed. The improved method is applied to describe the process of the shock through the air bubble by means of numerical simulation. Numerical results show that the method is superior to the traditional level set method.

Jet Flotation Column System Structure Design and Numerical Simulation of Two-Phase Flow

2012 ◽  
Vol 616-618 ◽  
pp. 655-661 ◽  
Author(s):  
Run Quan Yang ◽  
Huai Fa Wang ◽  
Jian Chao Liu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flow Model ◽  
Structure Design ◽  
System Structure ◽  
Two Phase ◽  
Air Bubble ◽  
Flotation Column ◽  
Column System ◽  
Simulation Results

A laboratory scale jet flotation column system was designed and air inflation for flotation column was provided by jet aerator with a chamber. In order to understand interior flow field distribution of jet aerator and flotation column, two-phase turbulent flow model was established by use of commercial computational fluid dynamics (CFD) software FLUENT 6.3.26. Modeling of the flow field was firstly established with GAMBIT 2.3.16; standard k-ε turbulence model and multiphase flow model MIXTURE were adopted for gas-liquid two-phase numerical simulation about jet aerator and flotation column. The simulation results show that gas-liquid two-phase mixing have been established by the cavity entrainment vortex flow in jet aerator with a chamber, and the distortion was really occurred although the reversed cone feed inlet have been designed, at the same time non-uniform distribution of air-bubble was also simulated. Simulation results can help to optimize the structure of the jet flotation column.

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