Air bubbles are used in chemical, biochemical, environmental, and food process for improving the heat and mass transfer. Due to the dominance of non-Newtonian liquids used in various process industries, an understanding of bubble rise in rheologically complex liquids has grown to be important. An experimental study of the bubble rise velocity and drag co-efficient at high Reynolds number in non...

Interleaflet cavitation in lipid bilayer membranes, or, shortly, intramembrane cavitation (IMC), is the formation of gas bubbles between the two leaflets of the membrane. The present paper focuses on the thermodynamics of IMC, namely, on the minimum work required to form an intramembrane cavity. The minimum work can be separated into two parts, one that depends on the volume and number of gas m...

In wet liquid foams, slow diffusion of gas through bubble walls changes bubble pressure, volume and wall curvature. Large bubbles grow at the expenses of smaller ones. The smaller the bubble, the faster it shrinks. As the number of bubbles in a given volume decreases in time, the average bubble size increases: i.e. the foam coarsens. During coarsening, bubbles also move relative to each other, ...

The evolution of an axi-symmetric Stokes bubble is considered when the bubble volume is changed. Linear stability analysis shows that an expanding spherical bubble is stable, while a shrinking spherical bubble is unstable. Numerical calculations of the time evolution shows that for certain initial condition, such a bubble can form cusps or near cusps or undergo topological change (pinching) bef...

For the operation of high void fraction bubbly flows in bubble columns, insight in primary parameters such as bubble size, shape and velocity as well as gas volume fraction is essential. At high gas volume fractions the flow system becomes opaque, ruling out non-intrusive optical techniques. As an alternative optical fibre probes can be used, which have the advantage of low cost, simplicity of ...

The present work investigates the acoustical absorption and scattering cross-sections of spherical bubble clouds subject to harmonic far field pressure excitation. Bubble dynamics effects and energy dissipation due to viscosity, heat transfer, liquid compressibility and relative motion of the two phases are included. The equations of motion for the average flow and for the bubble radius are lin...

We consider three-dimensional clusters of equal-volume bubbles packed around a central bubble and calculate their energy and optimal shape. We obtain the surface area and bubble pressures to improve on existing growth laws for three-dimensional bubble clusters. We discuss the possible number of bubbles that can be packed around a central one: the " kissing problem " , here adapted to deformable...

We consider three-dimensional clusters of equal-volume bubbles packed around a central bubble and calculate their energy and optimal shape. We obtain the surface area and bubble pressures to improve on existing growth laws for three-dimensional bubble clusters. We discuss the possible number of bubbles that can be packed around a central one: the "kissing problem," here adapted to deformable ob...

The interfacial area per unit volume is one of the key parameters for the design of multiphase reactors. In this work a population balance approach is applied to calculate the interfacial area density in a bubble column. The resulting transport equation for the arithmetic bubble volume is coupled with the balance equations for mass and momentum. In addition the physical absorption of the gas ph...