scholarly journals Passive Acoustic Method in Bubble Size Distribution Determination

2020 ◽  
Vol 320 ◽  
pp. 00031
Author(s):  
Stepan Gavrilev ◽  
Mikhail Ivanov
Keyword(s):  
Mathematical Model ◽  
Size Distribution ◽  
Gas Phase ◽  
Bubble Size ◽  
Acoustic Method ◽  
Bubble Size Distribution ◽  
Photometric Method ◽  
Air Bubbles ◽  
Hydrodynamic Properties ◽  
Passive Acoustic

The paper is considering existing methods for determining the gas phase hydrodynamic properties in liquid medium. This paper presents a passive hydroacoustic method for determining the air bubbles size distribution in water. Advantage of this method contrasting to the active ones lies in its invasiveness. Mathematical model proposed for converting the spectrum of noise emitted by a cloud of bubbles into size distribution was tested in a number of experiments. Experiments were carried out in a glass cubic reservoir filled with water. Experiment results were verified by comparison with the photometric method.

scholarly journals Numerical Simulation Study on Distribution of Bubble in Flow near Aerator Based on CFD-PBM Coupled Model in Tunnel

2021 ◽  
Vol 2021 ◽  
pp. 1-24
Author(s):  
Jiaming Lei ◽  
Jianmin Zhang ◽  
Lifang Zhang
Keyword(s):  
Size Distribution ◽  
Bubble Size ◽  
Numerical Models ◽  
Coupled Model ◽  
Bubble Size Distribution ◽  
Balance Model ◽  
Main Process ◽  
Air Bubbles ◽  
Air Concentration ◽  
Aerated Flow

The aerator can reduce erosion by mixing a large amount of air into the water in the solid wall area. The effectiveness of erosion reduction is mainly based on air concentration and its bubble size distribution. However, simultaneous simulation of the air concentration and its bubble size distribution in numerical simulations is still a hot and difficult area of research. Aiming at the downstream aerated flow of hydraulic aeration facilities, several numerical models, such as VOF, mixture, Euler, and Population Balance Model (PBM), are compared and verified by experiments. The results show that the CFD-PBM coupled model performs well compared to other conventional multiphase models. It can not only obtain the evolution law of the bubble distribution downstream of the aerator but also accurately simulate the recombination and evolution process of bubble aggregation and breakage. The Sauter mean diameter of the air bubbles in the aerated flow decreases along the way and eventually reaches a stable value. The bubble breakage is the main process in the development of the bubbles. It reveals the aeration law that the small air bubbles are closer to the bottom plate, while the large bubbles float up along the aerated flow, which provides a powerful support for the basic research on the mechanism of aeration and erosion reduction.

scholarly journals Acoustic Monitoring of the Dispersed Composition of Air Bubbles in Aeriated Waste Water Purification Processes

2021 ◽  
pp. 014-022
Author(s):  
S. A. Gavriliev ◽  
M. V. Ivanov
Keyword(s):  
Waste Water ◽  
Acoustic Method ◽  
Photometric Method ◽  
Experimental Plant ◽  
Air Bubbles ◽  
Flotation Column ◽  
Aeration System ◽  
Treatment Facilities ◽  
Passive Acoustic ◽  
Principal Possibility

A passive acoustic method is proposed for monitoring the dispersed composition of air bubbles, which determines the efficiency of wastewater treatment in facilities with aeration systems, in treatment facilities with aeration systems. The principal possibility of applying the method has been demonstrated on an experimental plant assembled on the basis of a flotation column. The size of the bubbles created by the flotation column aeration system was determined photometrically. It is shown that the error in determining the bubble radii by the proposed method relative to the photometric method was no more than 17.5%.

Experimental Study on Bubble Size Distribution in Gas-Liquid Reversed Jet Loop Reactor

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Rongshan Bi ◽  
Jiao Tang ◽  
Linxi Wang ◽  
Qingqing Yang ◽  
Meilan Zuo ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Size Distribution ◽  
Gas Phase ◽  
Flow Rate ◽  
Bubble Size ◽  
Draft Tube ◽  
Bubble Size Distribution ◽  
Image Processing Technique ◽  
Phase Flow ◽  
Loop Reactor

Abstract Bubble size distribution (BSD) is important for gas-liquid jet loop reactor (JLR)’s mass transfer performance of inter-phases. A self-designed reversed JLR was investigated with air-water system on the BSD. The CCD camera of particle imaging velocimetry (PIV) system and image processing technique were used to obtain the reliable photo. The influences of four parameters, gas phase flow rate, liquid phase flow rate, draft tube diameter and ejector mounting position, on the BSD were studied in detail. The results showed that the local BSD is accordance with log-normal distribution under the experimental conditions and the average diameter and BSD range increase with the increase of the gas phase flow rate, and decrease with the increase of the liquid phase flow rate, the downward movement of the nozzle installation position and the increase of the diameter of the draft tube.

Numerical Simulation With a CFD-PBM Model of Hydrodynamics and Bubble Size Distribution of a Rectangle Bubble Column

2016 ◽  
Author(s):  
Yi-Gang Ding ◽  
Xia Lu ◽  
Fu-Li Deng
Keyword(s):  
Size Distribution ◽  
Gas Phase ◽  
Bubble Size ◽  
Discrete Model ◽  
Bubble Column ◽  
Bubble Size Distribution ◽  
Bubble Coalescence ◽  
Complex Behavior ◽  
Gas Velocity ◽  
Superficial Gas Velocity

A coupled CFD-PBM (population balance mode) model is adopted to investigate complex behavior in a rectangle bubble column. In this work The Euler–Euler (E–E) model was adopted for the liquid phase and gas phase, while accounting for bubble coalescence and breakup a PBM discrete model was employed. The total gas holdup for a range of superficial gas velocities were studied and compared with the literature and modest agreement was found. The simulation result shows that the superficial gas velocity has great effect on bubble size distribution, and a wider bubble size distribution is found at higher superficial gas velocity. This indicates an increasing of the superficial gas velocity increases the bubble coalescence and break-up rate.

Physiochemical properties and reproducibility of air-based sodium tetradecyl sulphate foam using the Tessari method

2016 ◽  
Vol 32 (6) ◽  
pp. 390-396 ◽  
Author(s):  
Mike R Watkins ◽  
Richard J Oliver
Keyword(s):  
Size Distribution ◽  
Bubble Size ◽  
Bubble Size Distribution ◽  
Foam Density ◽  
Physiochemical Properties ◽  
Significant Difference ◽  
Experienced Operator ◽  
Sodium Tetradecyl Sulphate ◽  
Foam Production ◽  
Made In

Objectives The objectives were to examine the density, bubble size distribution and durability of sodium tetradecyl sulphate foam and the consistency of production of foam by a number of different operators using the Tessari method. Methods 1% and 3% sodium tetradecyl sulphate sclerosant foam was produced by an experienced operator and a group of inexperienced operators using either a 1:3 or 1:4 liquid:air ratio and the Tessari method. The foam density, bubble size distribution and foam durability were measured on freshly prepared foam from each operator. Results The foam density measurements were similar for each of the 1:3 preparations and for each of the 1:4 preparations but not affected by the sclerosant concentration. The bubble size for all preparations were very small immediately after preparation but progressively coalesced to become a micro-foam (<250 µm) after the first 30 s up until 2 min. Both the 1% and 3% solution foams developed liquid more rapidly when made in a 1:3 ratio (37 s) than in a 1:4 ratio (45 s) but all combinations took similar times to reach 0.4 ml liquid formation. For all the experiments, there was no statistical significant difference between operators. Conclusions The Tessari method of foam production for sodium tetradecyl sulphate sclerosant is consistent and reproducible even when made by inexperienced operators. The best quality foam with micro bubbles should be used within the first minute after production.

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.

CFD Simulation of Gas Dispersion in a Stirred Tank of Dual Rushton Turbines

2017 ◽  
Vol 15 (4) ◽  
Author(s):  
Xinju Li ◽  
Xiaoping Guan ◽  
Rongtao Zhou ◽  
Ning Yang ◽  
Mingyan Liu
Keyword(s):  
Flow Field ◽  
Size Distribution ◽  
Liquid Flow ◽  
Bubble Size ◽  
Great Influence ◽  
Gas Holdup ◽  
Bubble Size Distribution ◽  
Stirred Tank ◽  
Treatment Methods ◽  
Gas Dispersion

Abstract3D Eulerian-Eulerian model was applied to simulate the gas-liquid two-phase flow in a stirred tank of dual Rushton turbines using computational fluid dynamics (CFD). The effects of two different bubble treatment methods (constant bubble sizevs. population balance model, PBM) and two different coalescence models (Luo modelvs. Zaichik model) on the prediction of liquid flow field, local gas holdup or bubble size distribution were studied. The results indicate that there is less difference between the predictions of liquid flow field and gas holdup using the above models, and the use of PBM did not show any advantage over the constant bubble size model under lower gas holdup. However, bubble treatment methods have great influence on the local gas holdup under larger gas flow rate. All the models could reasonably predict the gas holdup distribution in the tank operated at a low aeration rate except the region far from the shaft. Different coalescence models have great influence on the prediction of bubble size distribution (BSD). Both the Luo model and Zaichik model could qualitatively estimate the BSD, showing the turning points near the impellers along the height, but the quantitative agreement with experiments is not achieved. The former over-predicts the BSD and the latter under-predicts, showing that the existing PBM models need to be further developed to incorporate more physics.

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