Bubbles plume

The terms Vr and Vt are terms that must be estimated. However, the multiplicative pair, VrVb, can be converted through analysis of a rising bubble plume (McWhirter and Hutter, 1989), as shown in Figure 8.18. The residence time of bubbles in the tank, tr, is given by tr = Fs/Qa. where Qa is the discharge of air into the tank. In addition, tr = hd/vr, where hd is the depth of water in the tank. Then,... 

Very often multiphase flow systems show inherent oscillatory behavior that necessitates the use of transient solution algorithms. Examples of such flows are encountered in bubbling gas-fluidized beds, circulating gas-fluidized beds, and bubble columns where, respectively, bubbles, clusters, or strands and bubble plumes are present that continuously change the flow pattern. 

Fig. 5 shows the bubble plume in front view (y-z plane) and profile (z-x plane). In both cases the photo is accompanied by a drawing schematizing the observed flows. For a constant gas input, the total gas/liquid contact surface is greater for small bubbles than for larger bubbles and the gas-liquid interactions are also greater. It was observed that the smaller the bubbles, the greater the liquid velocity, the more agitated and more turbulent the bubble plume, and the more spread out the plume at the air/liquid interface. 

Mudde, R.F. Simonin, O. Two- and three-dimensional simulations of bubble plume using a two-fluid model. Chem. Eng. Sci. 1999, 54, 5061-5069. 

Topham, D.R. Modelling of hydrocarbon bubble plumes to include gas hydrate formation. Chem. 

Deen et al [30] used the lift force in addition to the steady drag- and added mass forces in their dynamic 3D-model to obtain the transversal spreading of the bubble plume which is observed in experiments. A prescribed zero void wall boundary was used forcing the gas to migrate away from the wall. The continuous phase turbulence was incorporated in two different ways, using... 

Tomiyama [148] and Tomiyama and Shimada [150] adopted a N + 1)-fluid model for the prediction of 3D unsteady turbulent bubbly flows with non-uniform bubble sizes. Among the N + l)-fluids, one fluid corresponds to the liquid phase and the N fluids to gas bubbles. To demonstrate the potential of the proposed method, unsteady bubble plumes in a water filled vessel were simulated using both (3 + l)-fluid and two-fluid models. The gas bubbles were classified and fixed in three groups only, thus a (3 + 1)- or four-fluid model was used. The dispersions investigated were very dilute thus the bubble coalescence and breakage phenomena were neglected, whereas the inertia terms were retained in the 3 bubble phase momentum equations. No population balance model was then needed, and the phase continuity equations were solved for all phases. It was confirmed that the (3 + l)-fluid model gave better predictions than the two-fluid model for bubble plumes with non-uniform bubble... 

It is important to note that the particular experiment described here was conducted with a very low airflow into the bubble generator yielding a bubble plume that was barely perceptible in close-up video images of the water surface. Stronger airflow and a substantial bubble plume produced... 

At the sea surface, we may expect surfacing bubble plumes to contribute to surface renewal in the wake of breaking waves. This surface renewal will necessarily enhance air-sea gas exchange. It is our experience that only a small flux of bubbles is necessary to transform surface renewal, but this is difficult to quantify. It seems likely that bubbles are significant to surface renewal by small breaking waves, even when there is no obvious whitecap . 

Heeschen, K., Trehu, A., Collier, R.W., Suess, E., and Rehder, G, 2003. Distribution and height of methane bubble plumes on the Cascadia Margin characterized by acoustic imaging Geophysical Research Letters, 30 10.1029/2003GL016974. 

Warsito, W, and Fan, L.-S. (2005), Dynamics of spiral bubble plume motion in the entrance region of bubble columns and three phase fluidized beds using 3D ECT, Chemical Engineering Science, 60 6073-6084. 

Delnoij E. Westerweel J. Deen NG. Kuipers JAM. van Swaaij WPM. Ensemble correlation PIV applied to bubble plumes rising in a bubble column. Chem. Eng. Sci. 1999 54 5159-5171. 

Fig. 5.2. Formation of bubble plume under the breaking wave in the surf zone, (a) Attachment of jet on the surface (initiation of bubble plume generation) (b) Active phase of bubble plume generation [42 ms after (a)] (c) Bubble plume in silent phase [108 ms after (a)].

Leifer and G. de Leeuw, Bubble measurements in breaking-wave generated bubble plumes during the LUMINY wind-wave experiment, in Gas Transfer at Water Surfaces, eds. M. Donelan, W. Dreiman, E. Saltzman and R. Wanninkhof (AGU, Washington, DC, 2002), pp. 303-310. 

Maruyama, T., N. Kamishima and T. Mizuchina. Investigation of Bubble Plume Mixing by Comparison with Liquid Jet Mixing. 

Castello-Branco MASC, Schwerrtdfeger K (1994) Large-scale measurements of the physical characteristics of round vertical bubble plumes in liquids. Metall Mater Trans B 256 359-371... 

Bernard RS, Maier RS, Falvey HT (2000) A simple computational model for bubble plumes. Appl Math Model 24 215-233... 

Tomiyama [167] and Tomiyama and Shimada [169] adopted a (A -i- l)-fluid model for the prediction of 3D unsteady turbulent bubbly flows with non-uniform bubble sizes. Among the (A - - l)-fluids, one fluid corresponds to the liquid phase and the A fluids to gas bubbles. To demonstrate the potential of the proposed method, unsteady bubble plumes in a water filled vessel were simulated using both... 

Liibbert (1994) were among the first to find the unsteadiness of gas-liquid flows by means of a mixed Eulerian-Lagrangian code developed in-house the papers by Sokolichin and Eigenberger (1994) and Sokolichin et al (1997) illustrated this once more. More recent simulations of dispersed bubbly flows by Deen et al (2001), BombardeUi et al (2004), Zhang et al (2006), Dhotre et al (2009), and Niceno et al (2009) all exhibit the chaotic behavior of the bubbly plume and the liquid bulk. Wardle (2011) reported similar chaotic structures in the liquid-liquid mixture in an annular centrifugal contactor. 

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