Correlations of Bubble Diameter and Frequency for Air–Water System Based on Orifice Diameter and Flow Rate

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Hasan B. Al Ba'ba'a ◽  
Tarek Elgammal ◽  
Ryoichi S. Amano
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Bubble Diameter ◽  
Water System ◽  
Correlation Factor ◽  
Orifice Diameter ◽  
Clean Water ◽  
Bubble Frequency ◽  
Air Bubble ◽  
The Mean

Prediction correlations of air bubble diameter and frequency in stagnant clean water were established. Eleven different orifice diameters were tested under flow rate of 0.05–0.15 SLPM. The resulted bubble size and frequency were traced using high-speed camera. It was found that the mean Sauter diameter and bubble frequency are in the range of 3.7–6.9 mm and 6.4–47.2 bubbles per second, respectively. Nonlinear regression was performed to design the new correlations of estimating diameter and frequency with a correlation factor of 0.93 and 0.94, respectively. Flow rate and orifice size had the highest impact on the studied parameters.

Theoretical Modeling and Experimental Measurements of Single Bubble Dynamics From a Submerged Orifice in a Liquid Pool

2007 ◽  
Author(s):  
S. K. Kasimsetty ◽  
A. Subramani ◽  
R. M. Manglik ◽  
M. A. Jog
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Bubble Dynamics ◽  
Bubble Diameter ◽  
Liquid Pool ◽  
Orifice Diameter ◽  
Equivalent Diameter ◽  
Bubble Behavior ◽  
Balance Of Forces ◽  
Submerged Orifice

The dynamics of a single gas bubble, emanating from a submerged orifice in stagnant water has been explored both theoretically and experimentally. The mathematical model represents a fundamental balance of forces due to buoyancy, viscosity, surface tension, liquid inertia, and gas momentum transport, and the consequent motion of the gas-liquid interface. Theoretical solutions describe the dynamic bubble behavior (incipience, growth and necking) as it grows from a tip of a sub-millimeter-scale capillary orifice in an isothermal pool of water. These results are also found to be in excellent agreement with a set of experimental data that are obtained from optical high-speed micro-scale flow visualization. Variations in bubble shape, equivalent diameter, and growth times with capillary orifice diameter and air flow rates are outlined. These parametric trends suggest a two-regime ebullient transport: (a) a constant volume regime where the bubble diameter is not affected by the flow rate, and (b) a growing bubble regime where bubble size increases with flow rate.

scholarly journals COMPARISON OF DIFFERENT HYDRODYNAMIC CHARACTERISTICS OF AIR- WATER SYSTEM USING DISSIMILAR MOTIONLESS MIXERS

2021 ◽  
Author(s):  
Dr. Mazhar Hussain
Keyword(s):  
Mass Transfer ◽  
Power Consumption ◽  
Dissolved Oxygen ◽  
Bubble Diameter ◽  
Water System ◽  
Hydrodynamic Characteristics ◽  
Flow Rates ◽  
Static Mixers ◽  
Air Bubble ◽  
Transfer Study

The hydrodynamic characteristics of mixing fluids are always the points to consider in improvement of their mixing quality especially using motionless mixers normally stated as “Static Mixers”. Motionless mixing technique was adopted for Air-Water system with the advantage of negligible power consumption over dynamic mixers. Different hydrodynamic characteristics were experimented using “Baffle Type” static element and were compared to those of already used in recent studies. Dissolved oxygen content, Static mixer geometry (i.e. Baffle, Blade, Wheel, Plate and Needle), mixing fluids flow rates were chosen as variables and selected in this content as rate of mass transfer study which founds out to be significant using “Baffle Type” static element. Volumetric mass transfer was also achieved at higher scale which gives a clear indication of increase the mass transfer coefficient in between the comparison of “Baffle type” element and other mentioned elements. Pressure droplet and depletion in Air bubble size across static elements were visually perceived using Hg-Manometer and still photography respectively. A mathematical model was also developed portraying the Air bubble diameter at different flow rates for this system. Other hydrodynamics like higher Dissolved Oxygen (DO) Content, Less Power consumption were also found to be more advantageous for “Baffle Type” static element.

Flow over a stepped chute with and without macro-roughness elements

2004 ◽  
Vol 31 (5) ◽  
pp. 880-891 ◽  
Author(s):  
Mehmet Ali Kökpinar
Keyword(s):  
Water Flow ◽  
High Speed ◽  
Length Distribution ◽  
Air Entrainment ◽  
Air Concentration ◽  
Bubble Frequency ◽  
Two Phase ◽  
Air Bubble ◽  
Roughness Elements ◽  
Stepped Chute

High-speed two-phase flows over a 30° stepped flume were experimentally investigated using macro-roughness elements. The roughness elements included combinations of steps and horizontal strips. Local values of air concentration, air bubble frequency, and mean chord lengths were measured by a fiber-optical instrumentation system in the air–water flow region. The range of unit discharge of water was varied from 0.06 to 0.20 m2/s. Three step configurations were studied: (i) without macro-roughness elements, (ii) with macro-roughness elements on each step, and (iii) with macro-roughness elements on each second step (AMR configuration). The results were compared in terms of onset flow conditions and internal air–water flow parameters such as local air concentration, mean air bubble chord length distribution, and air bubble frequency in the skimming flow regime. It was observed that the AMR configuration produced the maximum free-surface aeration among the other configurations. This alternative step geometry has potential for less cavitation damage than conventional step geometry because of the greater air entrainment.Key words: stepped chute, air-entrainment, air-water flow properties, macro-roughness elements, skimming flow.

scholarly journals Preparation of suspensions of phospholipid-coated microbubbles by coaxial electrohydrodynamic atomization

2008 ◽  
Vol 6 (32) ◽  
pp. 271-277 ◽  
Author(s):  
U Farook ◽  
E Stride ◽  
M.J Edirisinghe
Keyword(s):  
Size Distribution ◽  
Flow Rate ◽  
Air Flow ◽  
Bubble Diameter ◽  
Mechanical Agitation ◽  
Preparation Methods ◽  
Scaling Equation ◽  
Human Body Temperature ◽  
The Mean ◽  
The Ideal

The use of phospholipid-coated microbubbles for medical applications is gaining considerable attention. However, the preparation of lipid-coated microbubble suspensions containing the ideal size and size distribution of bubbles still represents a considerable challenge. The most commonly used preparation methods of sonication and mechanical agitation result in the generation of polydisperse microbubbles with diameters ranging from less than 1 μm to greater than 50 μm. Efforts have been made via distinctly different techniques such as microfluidic and electrohydrodynamic bubbling to prepare lipid-coated microbubbles with diameters less than 10 μm and with a narrow size distribution, and recent results have been highly promising. In this paper, we describe a detailed investigation of the latter method that essentially combines liquid and air flow, and an applied electric field to generate microbubbles. A parametric plot was constructed between the air flow rate ( Q g ) and the lipid suspension flow rate ( Q l ) to identify suitable flow rate regimes for the preparation of phospholipid-coated microbubbles with a mean diameter of 6.6 μm and a standard deviation of 2.5 μm. The parametric plot has also helped in developing a scaling equation between the bubble diameter and the ratio Q g / Q l . At ambient temperature (22°C), these bubbles were very stable with their size remaining almost unchanged for 160 min. The influence of higher temperatures such as the human body temperature (37°C) on the size and stability of the microbubbles was also explored. It was found that the mean bubble diameter fell rapidly to begin with but then stabilized at 1–2 μm after 20 min.

scholarly journals Atomization of Water Jets and Sheets in Axial and Swirling Airflows

1979 ◽  
Author(s):  
R. D. Ingebo
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Drop Size ◽  
Unit Area ◽  
Water Flow Rate ◽  
Orifice Diameter ◽  
Drop Diameter ◽  
Water Jets ◽  
Test Conditions ◽  
The Mean

Axial and swirling airflows were used to break up water jets and sheets into sprays of droplets to determine the overall effects of orifice diameter, weight flow of air, and the use of an air swirler on fineness of atomization as characterized by mean drop size. A scanning radiometer was used to determine the mean drop diameter of each spray. Swirling airflows were produced with an axial combustor, 70-deg brake angle, air swirler. Water jets were injected axially upstream, axially downstream and cross stream into the airflow. In addition, pressure atomizing fuel nozzles which produced a sheet and ligament type of breakup were investigated. Increasing the weight flow rate of air or the use of an air swiler markedly reduced the spray mean drop size. Test conditions included a water flow rate of 68.0 liter per hour and airflow rates (per unit area) of 3.7 to 25.7 g per square cm per sec, at 293 K and inlet-air static pressures of 1.01 × 105 to 1.98 × 105 N/m2.

Bubble Behavior and Mean Diameter in Subcooled Flow Boiling

1996 ◽  
Vol 118 (1) ◽  
pp. 110-116 ◽  
Author(s):  
O. Zeitoun ◽  
M. Shoukri
Keyword(s):  
Heat Flux ◽  
Mass Flux ◽  
High Speed ◽  
Flow Boiling ◽  
Bubble Diameter ◽  
Image Processing Technique ◽  
Bubble Behavior ◽  
Subcooled Flow Boiling ◽  
Subcooled Flow ◽  
The Mean

Bubble behavior and mean bubble diameter in subcooled upward flow boiling in a vertical annular channel were investigated under low pressure and mass flux conditions. A high-speed video system was used to visualize the subcooled flow boiling phenomenon. The high-speed photographic results indicated that, contrary to the common understanding, bubbles tend to detach from the heating surface upstream of the net vapor generation point. Digital image processing technique was used to measure the mean bubble diameter along the subcooled flow boiling region. Data on the axial area-averaged void fraction distributions were also obtained using a single-beam gamma densitometer. Effects of the liquid subcooling, applied heat flux, and mass flux on the mean bubble size were investigated. A correlation for the mean bubble diameter as a function of the local subcooling, heat flux, and mass flux was obtained.

Research on Bubble Growth and Frequency at Higher System Pressure in Narrow Rectangular Channel

2013 ◽  
Author(s):  
Jian Hu ◽  
Puzhen Gao ◽  
Qiang Zheng
Keyword(s):  
Heat Flux ◽  
Mass Flux ◽  
Bubble Growth ◽  
High Speed ◽  
Rectangular Channel ◽  
Bubble Diameter ◽  
Digital Camera ◽  
Bubble Frequency ◽  
Heating Wall ◽  
System Pressure

In present work, the characteristics of bubble growth and frequency were visually observed in a narrow rectangular channel using high-speed digital camera. The experiment was done over the following range of conditions: pressure, 0.55MPa; mass flux, 300–500kg/(m2·s); heat flux, 86.4–225.7 kW/m2; and inlet subcooling, 25.5–45.5K. The system pressure has a significant effect on the bubble growth. Experimental results show that the bubble diameters are just about 0.15mm under higher system pressure and the period during which bubbles attaching to the nucleate site is very short, or even unnoticeable. The bubbles keep growing when slide along the heating wall rather than lifting off the surface, and the bubbles rarely collapse under the working conditions. When the mass flux is high, the bubble diameter increases with increasing the heat flux, but when the mass flux is low, the variation trend of bubble diameters expresses no obvious law. The effect of thermal parameters on bubble frequency is also significant. When the mass flux is low, the bubble frequency decreases with increasing the heat flux or inlet subcooling, however when the mass flux is high, the bubble frequency increases first and then decreases. Generally, the bubble frequency increases with increasing the mass flux.

Experimental Study of Single-Bubble Dynamics in Isothermal Liquid Pools: Effects of Fluid Properties, Orifice Diameter and Flow Rate

2007 ◽  
Author(s):  
A. Subramani ◽  
M. A. Jog ◽  
R. M. Manglik
Keyword(s):  
Surface Tension ◽  
Flow Rate ◽  
High Speed ◽  
Bubble Dynamics ◽  
Processing System ◽  
Single Bubble ◽  
Orifice Diameter ◽  
Growth Time ◽  
Interfacial Behavior ◽  
Fluid Properties

The dynamics of a single bubble as it grows at and eventually detaches from the tip of submerged capillary orifices in isothermal pools of pure liquids of varying fluid properties is studied experimentally. The transient interfacial behavior around the evolving isolated bubble (from inception through growth, necking, and detachment) is mapped by means of optical micro-scale flow visualization that uses a high-speed high-resolution digital camera and image processing system. Parametric effects of capillary orifice diameter (do = 0.32, 1.0, and 1.76 mm), air flow rate (2 ≤ Q˙ ≤ 20 ml/min), and liquid properties (surface tension and viscosity), on the bubbling signature (growth time, departure diameter, and bubble interval) are explored and highlighted. It is found that bubble evolution, in a first order scaling, can be correlated by a balance of forces due to buoyancy, viscosity, surface tension, liquid inertia, and gas momentum transport at the transient gas-liquid interface.

Articulatory Behavior Pre and Post Full-Mouth Tooth Extraction and Alveoloplasty

1980 ◽  
Vol 23 (3) ◽  
pp. 630-645 ◽  
Author(s):  
Gerald Zimmermann ◽  
J.A. Scott Kelso ◽  
Larry Lander
Keyword(s):  
Control Subject ◽  
High Speed ◽  
Tooth Extraction ◽  
Kinematic Parameters ◽  
Experimental Conditions ◽  
Mean Values ◽  
Articulatory Movements ◽  
The Mean ◽  
Experimental Subjects ◽  
Normal Speech

High speed cinefluorography was used to track articulatory movements preceding and following full-mouth tooth extraction and alveoloplasty in two subjects. Films also were made of a control subject on two separate days. The purpose of the study was to determine the effects of dramatically altering the structural dimensions of the oral cavity on the kinematic parameters of speech. The results showed that the experimental subjects performed differently pre and postoperatively though the changes were in different directions for the two subjects. Differences in both means and variabilities of kinematic parameters were larger between days for the experimental (operated) subjects than for the control subject. The results for the Control subject also showed significant differences in the mean values of kinematic variables between days though these day-to-day differences could not account for the effects found pre- and postoperatively. The results of the kinematic analysis, particularly the finding that transition time was most stable over the experimental conditions for the operated subjects, are used to speculate about the coordination of normal speech.

SCIENTIFIC AND ENGINEERING PRINCIPLES OF EFFICIENT FUEL USE AND ENVIRONMENTALLY FRIENDLY GAS COMBUSTION IN STOVE PLATES. PART 1. MODERN STATE-OF-THE-ART AND DIRECTIONS FOR IMPROVEMENT THE GAS BURNING IN DOMESTIC GAS COOKERS

2017 ◽  
pp. 3-18 ◽  
Author(s):  
B.S. Soroka ◽  
V.V. Horupa
Keyword(s):  
Natural Gas ◽  
Flow Rate ◽  
Gas Flow ◽  
Renewable Energy Sources ◽  
Combustion Process ◽  
Orifice Diameter ◽  
Firing Process ◽  
Gas Flow Rate ◽  
Gas Combustion ◽  
Gas Stoves

Natural gas NG consumption in industry and energy of Ukraine, in recent years falls down as a result of the crisis in the country’s economy, to a certain extent due to the introduction of renewable energy sources along with alternative technologies, while in the utility sector the consumption of fuel gas flow rate enhancing because of an increase the number of consumers. The natural gas is mostly using by domestic purpose for heating of premises and for cooking. These items of the gas utilization in Ukraine are already exceeding the NG consumption in industry. Cooking is proceeding directly in the living quarters, those usually do not meet the requirements of the Ukrainian norms DBN for the ventilation procedures. NG use in household gas stoves is of great importance from the standpoint of controlling the emissions of harmful components of combustion products along with maintenance the satisfactory energy efficiency characteristics of NG using. The main environment pollutants when burning the natural gas in gas stoves are including the nitrogen oxides NOx (to a greater extent — highly toxic NO2 component), carbon oxide CO, formaldehyde CH2O as well as hydrocarbons (unburned UHC and polyaromatic PAH). An overview of environmental documents to control CO and NOx emissions in comparison with the proper norms by USA, EU, Russian Federation, Australia and China, has been completed. The modern designs of the burners for gas stoves are considered along with defining the main characteristics: heat power, the natural gas flow rate, diameter of gas orifice, diameter and spacing the firing openings and other parameters. The modern physical and chemical principles of gas combustion by means of atmospheric ejection burners of gas cookers have been analyzed from the standpoints of combustion process stabilization and of ensuring the stability of flares. Among the factors of the firing process destabilization within the framework of analysis above mentioned, the following forms of unstable combustion/flame unstabilities have been considered: flashback, blow out or flame lifting, and the appearance of flame yellow tips. Bibl. 37, Fig. 11, Tab. 7.

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