Download or read book A Parametric Investigation of Gas Bubble Growth and Pinch off Dynamics from Capillary tube Orifices in Liquid Pools written by Deepak Saagar Kalaikadal and published by . This book was released on 2012 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: The air-bubble dynamics phenomena in adiabatic liquid pools has been studied so as to present a better understanding of the parameters which that govern the process of ebullience, bubble growth and departure from a submerged capillary-tube orifice. The orifice diameter is found to directly dictate the bubble departure diameter, and the pinch-off is controlled by a characteristic neck-length. To study the role of orifice size on the growth and departure of adiabatic single bubbles, experiments were performed with different diameter capillary tubes submerged in of distilled de-ionized water as well as some other viscous liquids. A correlation has been developed based on the experimental data of this study along with those reported by several others in the literature. The predictions of this correlation agree very well with measured data for water as well as several other more viscous liquids. It is also found that the bubble departure diameter is the same as the orifice diameter when the latter equals twice the capillary length. The phenomenon of bubble necking and departure was explored experimentally and through a scaling analysis. Experiments were performed with five different liquids (water, ethanol, ethylene glycol, propylene glycol, and glycerol) to extract the departure neck-lengths for isolated gas bubbles at pinch-off from the capillary orifice. A scaling analysis of the experimental data indicated that the bubble neck-length at departure or pinch-off was predicted by a balance of buoyancy, viscous and surface tension forces. These were established to be represented by the Galilei and Morton numbers, and a power-law type predictive correlation has been shown to be in excellent agreement with the available data over a wide range of liquid properties. To characterize and model the growth and departure of single bubbles in different liquid pools, a theoretical model has been established. The motion of the gas-liquid interface has been modeled as a scaled force balance involving buoyancy, gas-momentum, pressure, surface tension, inertia and drag. With one-dimensional scaling of these forces, the model captures the incipience, growth, necking and departure of a bubble as it emerges from the orifice. Here necking and pinch-off is modeled based on the newly developed neck-length correlation. The results are compared with experimental data and are found to be in excellent agreement for a range of liquids, orifice sizes and flow rates. The predictions highlight the variations in bubble equivalent diameters at departure with orifice sizes, flow rates and fluid properties, and they further reiterate the well-established two-regime theory of bubble growth. The latter involves (a) the constant volume regime, where the bubble volume remains near constant and relatively independent of flow rate, and (b) the growing bubble regime, where the size of the bubble increases proportionately with the gas flow rate. Finally, the complex nature of ebullience in aqueous surfactant solutions has been studied using the reagents FS-50, SDS, and CTAB. The influence of the modulated liquid surface tension or more specifically, the role of the time dependent dynamic surface tension on the formation and departure of adiabatic bubbles has been investigated. Comparative studies have been undertaken to investigate the effect of time-dependent surface tension relaxation in surfactant solutions as opposed to ebullience in pure liquids with the same equilibrium surface tensions. Results highlight the effects of the surfactant's molecular weight on the adsorption-desorption kinetics, and the consequent influence on ebullience. It has been established that the bubbling characteristics in surfactant solutions are, in the first order, governed by the dynamic surface tension of the solute-solvent system.

Download or read book Theoretical Modeling and Correlational Analysis of Single Bubble Dynamics from Submerged Orifices in Liquid Pools written by and published by . This book was released on 2008 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: The growth dynamics of a single gas bubble from inception to departure, emanating from a submerged capillary tube orifice in quiescent liquid pools has been theoretically modeled. 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 evolving gas-liquid interface. Theoretical solutions describe the dynamic bubble behavior (incipience, growth, necking and departure) as it grows from the tip of a capillary tube orifice in an isothermal pure liquid pool. Also complete Navier Stokes equations are solved using VOF model to simulate the different stages in the evolution of the bubble. Variations in bubble shapes and sizes, equivalent diameter, and growth times with capillary orifice diameter and air flow rates are outlined. These results are also found to be in excellent agreement with the experimental data available in the literature. The 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. The experimental data available in the literature for a wide range of liquids, flow rates and orifice sizes are analyzed to develop regime maps that characterize these two regimes. For a given liquid, the transition from the constant volume regime and the growing bubble regime is determined by the non-dimensional parameter, BoFr0.5 = 1, that defines the interaction between buoyancy, surface tension and inertial forces. Correlation for isolated adiabatic bubble departure diameters is also developed based on a non-linear regression analysis of experimental data. The correlation considers the effects of thermo physical properties of the gas and liquid phases, orifice diameters and gas flow rates, and describes the experimental data published in the literature with in " 10 percent.

Download or read book Experimental Investigation of Aperiodic Bubbling from Submerged Capillary tube Orifices in Liquid Pools written by Vignesh Gopal and published by . This book was released on 2013 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adiabatic, multiple bubble formation or aperiodic bubbling in pure liquids is experimentally investigated. The process of bubble formation, coalescence, and pairing has been captured using a high-speed, high-resolution digital camera. The visual data were processed using image processing software to determine the bubble interval, bubble diameter, and coalescence distance from orifice tip, among other characteristics. The effects of orifice diameter (0.15 dsubo/sub/lsubc

Download or read book Computational Assessments on Bubble Dynamics Applied to Flotation Cells written by Asif Mammadov and published by . This book was released on 2016 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Au, Ag, Hg, many other metals, diamond, coal, oil and tar sands are extracted by flotation process. We can define flotation as a single, most significant unit operation in mineral processing, used in extraction of all kinds of minerals. A study of air bubble dynamics and gas-liquid multiphase flow is important for the design, development and understanding of industrial processes such as bubble column reactors, flotation cells and boilers. Hence bubble generation and attachment is an important part of flotation process. In order to understand bubble dynamics, we built models of single bubble systems. The growth and detachment of air bubble from single orifice in water tank was studied. An axisymmetric model based on the Volume of Fluid method, available in ANSYS-Fluent software was used for simulation of air bubble rising in water. Numerous numerical simulations were carried out using an axisymmetric domain with different orifice diameters (0.8, 0.4 mm), air inlet velocities (50, 150 mlph) and phase surface tensions (50, 72 mN/m). Bubble growth and rise velocity were studied and validated against experimental data published in literature. Relative good agreement was achieved. Velocity profiles of the rising bubbles as well as Reynolds, Weber and Capillary numbers were calculated. Effect of surface tension and nozzle diameter to bubble size and dynamics were discussed. It was shown that smaller surface tension of the system yields to smaller bubble size which is more favorable for flotation process.

Download or read book Experimental Characterization of Bubble Dynamics in Isothermal Liquid Pools written by and published by . This book was released on 2008 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: A sample study was carried out with aqueous SDS solution to observe the transient bubble dynamics of air bubbles in the presence of surface active chemicals. The bubble formation appeared to follow a trend similar to those observed with pure liquids, though the necessity of a much detailed investigation was evident to completely understand the effect of dynamic surface tension reduction on the complex phenomenon of bubble ebullience.

Download or read book Investigation of the Fluid Dynamics of a Gas Jet Expansion Ina Liquid Pool written by L. Meyer and published by . This book was released on 1994 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Theoretical and Experimental Investigation of the Liquid Flow Around a Gas Bubble written by Aart Jan Van Bekkum and published by . This book was released on 1985 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book THE DYNAMICS OF GAS VAPOR BUBBLES IN BINARY SYSTEMS written by Poul Scheel Larsen and published by . This book was released on 1963 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of the Fluid Dynamics of a Gas Jet Expansion in a Liquid Pool written by L. Meyer and published by . This book was released on 1994 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation of Gas Bubble Injection from Single Nozzles Into Water and Liquid Metal Pools written by Devin W. Gray and published by . This book was released on 2008 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation of Gas Bubble Generation and Detection in Water and Mercury written by Stuart Alexander Walker and published by . This book was released on 2010 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: The pressure increase attributed to the energy deposition in the liquid metal target of the Spallation Neutron Source results in cavitation and pitting erosion of the target pressure boundary. Introducing compressibility in the form of small gas bubbles will extend the lifetime of the target vessel. The pressure rise caused by the beam energy deposition occurs in one microsecond, which encourages use of bubbles of radius less than 20 microns, such that the bubble response to pressure change is adequately fast. Gas volume fraction near 0.5% is sufficient to accommodate the mercury volumetric expansion and reduce the pressure rise. Bubble production and detection technologies are developed herein to allow control of the bubble diameter and volume fraction in an opaque liquid metal. This research infers bubble size in the form of a probability density function using dynamic gas delivery pressure and mass flow, and passive acoustic emissions at bubble birth, for a single orifice bubbler. Terminal rise velocities are also measured and used to infer bubble diameter. The gas volume fraction is inferred from the acoustic sound speed using the so-called low frequency Wood's Limit model for sound speed in a bubbly media.

Download or read book Numerical Approaches to Predict Bubble Growth in Viscous Liquids Using Polynomial Profiles written by Praveen K. Vasam and published by . This book was released on 2003 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of the Fluid Dynamics of a Gas Jet Expansion in a Liquid Pool written by Leonhard Meyer and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mathematical Modeling of Bubble Growth in Turbulent Flow written by Ali F. Abu-Bakr and published by LAP Lambert Academic Publishing. This book was released on 2014-12-25 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical modeling of bubbles dynamics is presented in turbulent flow to study the behaviour of vapour growth bubble between two phases (vapour-superheated liquids) flow. Theoretical study of the growth problem is solved analytically in terms of initial void fraction and initial bubble velocity. The growth problem in a viscous superheated liquid is investigated under the proposed pressure of Plesset and Zwick. The growth of bubble radius in a constant and variable dynamical viscosity is studied. The effect of constant and variable dynamical viscosity for two different cases of pressure is studied. The initial time of growth of vapour bubbles between two phase laminar-turbulent flow is introduced in thermal stage. This book is suitable and will be interesting for all researchers in related fields.

Download or read book Theoritical Investigation on the Dynamics of Cavitation Bubble Growth written by Bror Persson and published by . This book was released on 1974 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bubble Growth Dynamics in Boiling written by Anthony James Robinson and published by . This book was released on 2003 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mechanisms which govern the growth of a spherical vapour bubble in an unbounded liquid were exposed by investigating the complex interaction between the heat transfer and the fluid flow surrounding a bubble as it grows from inception, through the various growth stages, to diffusion controlled growth. The influence of system pressure and liquid superheat were also investigated.

Download or read book Theoretical and Experimental Studies of Bubble Growth at an Orifice written by Tania Dos Santos Moreno Vidinha and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: