Abstract In this study, hydrodynamics and heat transport during the impact of single multiple drops onto a hot wall are studied numerically. The transfer in vicinity three-phase contact line, where solid, liquid vapour meet, contributes significantly to global transfer. microscale processes region line analysed using lubrication approximation. results form correlations integrated into an overal...

The mixing of immiscible oil and water by a pitched blade turbine in cylindrical vessel is studied numerically. Three-dimensional simulations combined with hybrid front-tracking/level-set method are employed to capture the complex flow interfacial dynamics. A large eddy simulation approach, Lilly–Smagorinsky model, simulate turbulent two-phase dynamics at Reynolds numbers $Re=1802{-}18\ 026$ . ...

In bubble-laden flows with large local or global void fraction the distance between bubbles is small so that these interact with a certain probability. During interaction, the bubble can either bounce or undergo coalescence, depending on the nature of the interaction. Coalescence as well as bubble breakup alter the bubble size distribution and consequently change the dynamics of individual bubb...

This paper reports the direct and precise measurement of bubble coalescence in salt solutions using microfluidics. We directly visualized the bubble coalescence process in a microchannel using high-speed imaging and evaluated the shortest coalescence time to determine the transition concentration of sodium halide solutions. We found the transition concentration is ion-specific, and the capacity...

A bubble coalescence model is developed using an Euler–Lagrangian approach for unstructured grids. The Eulerian carrier fluid is solved using large-eddy simulation (LES) and the Lagrangian particle motion is solved with equations relating the turbulent motion of the carrier fluid to forces on each discrete bubble. The collision process is deterministic; bubble–bubble collisions are assumed to b...

We analyse two-dimensional clamped parallel elastic sheets which are partially immersed in liquid as a model for elasto-capillary coalescence. In the existing literature this problem is studied via minimal energy analysis of capillary and elastic energies of the post-coalescence state, yielding the maximal stable post-coalescence bundle size. Utilizing modal stability analysis and asymptotic an...

We present the results of experiments studying droplet coalescence in a dense layer of emulsion droplets using microfluidic circuits. The microfluidic structure allows direct observation of collisions and coalescence events between oil droplets dispersed in water. The coalescence rate of a flowing hexadecane-in-water emulsion was measured as a function of the droplet velocity and droplet concen...

We describe a single microfluidic device and two methods for the passive storage of aqueous drops in a continuous stream of oil without any external control but hydrodynamic flow. Advantages of this device are that it is simple to manufacture, robust under operation, and drops never come into contact with each other, making it unnecessary to stabilize drops against coalescence. In one method th...

A parameterization for cloud processing is presented that calculates activation of aerosol particles to cloud drops, cloud drop size, and pH-dependent aqueous phase sulfur chemistry. The parameterization is implemented in the global aerosol-climate model ECHAM5-HAM. The cloud processing parameterization uses updraft speed, temperature, and aerosol size and chemical parameters simulated by ECHAM...

Two-phase systems of microstructured complex fluids are an important class of engineering materials. Their flow behaviour is interesting because of the coupling among three disparate length scales: molecular or supra-molecular conformation inside each component, mesoscopic interfacial morphology and macroscopic hydrodynamics. In this paper, we propose a diffuse-interface approach to simulating ...