Author: Sara MoghtadernejadPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Dynamics of Droplet Shedding and Coalescence Under the Effect of Shear Flow
Author: Sara MoghtadernejadNumerical Study of Droplet Coalescence and Droplet Shedding on Surfaces with Various Wettabilities
Author: Mehran Mohammadi FarhangiPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Dynamics of Droplets
Author: Arnold FrohnPublisher: Springer Science & Business Media
ISBN: 9783540658870
Category : Science
Languages : en
Pages : 308
Book Description
The book deals with the dynamical behaviour of single droplets and regular droplet systems. After a short description of the theoretical background, the different experimental facilities and methods necessary for the investigation of single droplets are described in detail. A summary of important applications is included.
A Theoretical, Numerical, and Experimental Study of Trapped Droplet Coalescence and Mixing, Passively and Under Electric Field
Author: Alireza Karbalaei BabaPublisher:
ISBN:
Category :
Languages : en
Pages : 106
Book Description
Passive and electrically active coalescence and mixing of pairs of trapped squeezed nanodroplets were studied in this work. PDMS-glass microfluidic devices were designed and fabricated using multilevel photolithography technique. Flow-focusing method was used to generate nanoliter droplets of died glycerol inside oleic acid. The effect of factors such as flow rates and their ratio, interfacial tension, and viscosities on the size and frequency of droplet generation was studied and concluded by demonstrating the capillary number effect. A passive droplet trapping technique based on minimizing the surface energy of the droplets was employed to minimize the shear flow effects and increase the accuracy of passive coalescence and mixing experiments. The theoretical platform was presented for the analysis of this multiphase problem and a numerical solver was developed based on the lattice Boltzmann method to simulate the passive and electro-coalescence of the droplet pairs. Mixing of nanodroplets was studied by discussing the contributing mixing time scales and passive mixing of glycerol nanodroplets was experimentally realized. The rate of passive mixing percentage was derived by performing image processing and its exponential asymptotical behavior was presented. This study provided physical perspectives for droplet coalescence and mixing and can be extended in several numerical and experimental aspects.
Dynamics of Drop Impact and Coalescence at a Liquid/liquid Interface
Author: Ahmad Zulfaa Mohamed-KassimPublisher:
ISBN:
Category :
Languages : en
Pages : 360
Book Description
Applied Mechanics Reviews
Author: Controlling Drop Coalescence Using Nano-engineered Surfaces
Author: Manuel Corral (Jr.)Publisher:
ISBN:
Category :
Languages : en
Pages : 46
Book Description
The dynamics of drop coalescence are explored on micro-scale surface features for the first time. Drop coalescence is defined as a process by which two or more droplets, bubbles or particles merge during contact to form a single droplet, bubble or particle. There are two regimes that limit the dynamics of drop coalescence of a liquid. The first is regime is limited by the viscosity of the droplets. The second regime is limited by inertial forces caused by the motion that merges the two droplets. Currently, much work has been done to study drop coalescence in a liquid-liquid environment and the phenomenon has been well defined and modeled. Previous work has been done to understand liquid-liquid drop coalescence using liquids with varying viscosity, but the effects of solid micro-textured surfaces on drop coalescence dynamics of low density liquids, such as water, have not yet been analyzed and quantified. Very little has been studied about drop coalescence in a solid-liquid-air interface. In this thesis, drop coalescence in its inertial regime will be defined in low viscosity liquid, water, on surfaces with varying wettability and micro-scale features. Surfaces include microstructures consisting of a regular array of square posts defined by the aspect ratio of the posts and the spacing between the posts. This work focuses on the development of a fundamental understanding and physical model of micro-scale surface texture effects on drop coalescence to provide aid in future surface design applications. These applications could allow for the controlling of this phenomenon to promote drop-wise condensation in order to increase efficiencies of condensers or to aid in water-oil separation procedures.
Study and Simulation of the Interaction Between Two Drops Under Shear Flow and Its Relation to Coalescence
Author: Ricardo Falla AvilaHeat transfer in data centers, volume II
Author: Chengbin ZhangPublisher: Frontiers Media SA
ISBN: 2832507484
Category : Technology & Engineering
Languages : en
Pages : 89
Book Description
Simulations of Droplet Interactions with Lattice Boltzmann Methods
Author: Orest ShardtPublisher:
ISBN:
Category : Computer simulation
Languages : en
Pages : 134
Book Description
Interactions between droplets were studied using two lattice Boltzmann methods (LBMs). The Shan-Chen LBM, in which repulsive forces between fluids maintain phase separation, was used to simulate systems with three immiscible components. The simulations demonstrated the three equilibrium configurations of two droplets in a third fluid: adhering, separated, and engulfed. Simulations of adhering droplet pairs, called Janus droplets due to their two-sided structure, in shear flow revealed the structure of the internal flow and the dependence of the rotation rate on the orientation of the droplet. A second type of interaction between droplets was simulated with the free-energy binary-liquid LBM: binary droplet collisions in confined simple shear flow. The conditions for coalescence were quantified and the effects of geometry and the parameters of this Cahn-Hilliard-type phase field model on the critical conditions were examined. Two parameters of the phase field model, the thickness of the diffuse interface and the mobility of the phase field, are important. Simulations with highly-resolved droplets, with radii spanning 200 lattice nodes, were used to determine the minimum film thickness before coalescence, its relationship to the interface thickness, and the effect of the mobility on the evolution of the minimum distance between the droplet interfaces during collisions. The critical conditions for coalescence in these simulations were compared with published experiments with polymers. Unlike the experimental polymer system, the interfaces of interacting droplets are often charged, as in the case of oil-water emulsions. To simulate such liquid systems, the free-energy binary-liquid LBM was coupled with an iterative finite difference solver for the linearized Poisson-Boltzmann equation that describes the electrostatic potential near a charged surface in an electrolyte solution. Simulations of collisions between charged droplets with constant zeta potentials in a sheared electrolyte showed the effects of surface charge on the critical conditions for coalescence.