Surface area prediction for two phase drops in an immiscible liquid

1980 ◽  
Vol 58 (3) ◽  
pp. 318-324 ◽  
Author(s):  
K. L. Pinder
Keyword(s):  
Surface Area ◽  
Immiscible Liquid ◽  
Two Phase

Surface area prediction for two phase drop in an immiscible liquid

1981 ◽  
Vol 59 (3) ◽  
pp. 410-413
Author(s):  
Kazuya Higeta ◽  
Yasuhiko H. Mori ◽  
K. L. Pinder ◽  
S. Gnanasundaram ◽  
T. E. Degaleesan ◽  
...  
Keyword(s):  
Surface Area ◽  
Immiscible Liquid ◽  
Two Phase

scholarly journals Direct contact evaporation of a single two-phase bubble in a flowing immiscible liquid medium. Part I: two-phase bubble size

2019 ◽  
Vol 55 (9) ◽  
pp. 2593-2603
Author(s):  
Hameed B. Mahood ◽  
Ali Sh. Baqir ◽  
Al-Dunainawi Yousif ◽  
Anees A. Khadom ◽  
Alasdair N. Campbell
Keyword(s):  
Liquid Medium ◽  
Bubble Size ◽  
Direct Contact ◽  
Immiscible Liquid ◽  
Two Phase

scholarly journals Simulated Microstructural Evolution and Design of Porous Sintered Wicks

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Karthik K. Bodla ◽  
Suresh V. Garimella
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Transport Properties ◽  
Effective Thermal Conductivity ◽  
Surface Area ◽  
Microstructural Evolution ◽  
Ad Hoc ◽  
Three Dimensions ◽  
Two Phase ◽  
Sintering Kinetics

Porous structures formed by sintering of powders, which involves material-bonding under the application of heat, are commonly employed as capillary wicks in two-phase heat transport devices such as heat pipes. These sintered wicks are often fabricated in an ad hoc manner, and their microstructure is not optimized for fluid and thermal performance. Understanding the role of sintering kinetics—and the resulting microstructural evolution—on wick transport properties is important for fabrication of structures with optimal performance. A cellular automaton model is developed in this work for predicting microstructural evolution during sintering. The model, which determines mass transport during sintering based on curvature gradients in digital images, is first verified against benchmark cases, such as the evolution of a square shape into an area-preserving circle. The model is then employed to predict the sintering dynamics of a side-by-side, two-particle configuration conventionally used for the study of sintering. Results from previously published studies on sintering of cylindrical wires are used for validation. Randomly packed multiparticle configurations are then considered in two and three dimensions. Sintering kinetics are described by the relative change in overall surface area of the compact compared to the initial random packing. The effect of sintering parameters, particle size, and porosity on fundamental transport properties, viz., effective thermal conductivity and permeability, is analyzed. The effective thermal conductivity increases monotonically as either the sintering time or temperature is increased. Permeability is observed to increase with particle size and porosity. As sintering progresses, the slight increase observed in the permeability of the microstructure is attributed to a reduction in the surface area.

A Theory of Electrophoresis of Emulsion Drops in Aqueous Two-Phase Polymer Systems

1981 ◽  
Vol 9 ◽  
Author(s):  
Samuel Levine
Keyword(s):  
Continuous Phase ◽  
Immiscible Liquid ◽  
Ion Distribution ◽  
Two Phase ◽  
Relaxation Effects ◽  
Liquid Phases ◽  
Increase With Increase ◽  
Aqueous Mixture ◽  
Idealised Model ◽  
Two Phases

ABSTRACTTwo immiscible liquid phases form when an aqueous mixture of the electrically neutral polymers dextran and polyethylene glycol are equilibrated at sufficient concentrations. Certain supporting electrolytes which contain sulphate, phosphate or citrate ions partition unequally between the phases, and in their presence, electrophoresis of a drop of one phase suspended in the other is observed, with large mobilities. These mobilities depend linearly on the radius of the drop and the direction of the drop's motion is reversed when the disperse phase and the continuous phase are interchanged. When those ions which produce electrophoresis are present the potential Implied by the direction of electrophoresis is opposite to the Donnan potential observed between the two phases. To explain these results, we postulate an electric dipole layer associated with a mixture of oriented polymer molecules at the surface of a drop. In addition, a potential difference between the interiors of the two phases results from the unequal ion distribution. For the idealised model of a surface layer of point dipoles the inner and outer diffuse layers carry net charges equal in magnitude but opposite in sign. The classical theory of electrophoresis due to Henry, Overbeek and Booth is adapted to the motion of an emulsion drop under an electric field when diffuse ionic layers are present inside and outside the drop. Relaxation effects are treated for the case where the two diffuse layer thicknesses are small compared with the drop radius. An expression is obtained for the electrophoretic mobility of a drop which depends linearly on radius and also shows an increase with increase in salt concentration. The theory presented here is related to the work of Levich.

Rapid Boiling of a Two-Phase Droplet in an Immiscible Liquid at High Superheat

2009 ◽  
Vol 131 (12) ◽  
Author(s):  
Herman D. Haustein ◽  
Alon Gany ◽  
Ezra Elias
Keyword(s):  
Heat Transfer ◽  
High Heat ◽  
Immiscible Liquid ◽  
Two Phase ◽  
Liquid Environment ◽  
Transfer Rates ◽  
High Heat Transfer ◽  
Boiling Process ◽  
High Superheat ◽  
Transient Boiling

This work studies experimentally the rapid boiling of a droplet rising in a host liquid environment, within a range of superheats (0.2<Ja∗<0.5) not previously investigated. The direct-contact rapid-boiling process has many advantages in the fields of heat exchange and multiphase flow. By taking into account the superheat, heat transfer, and hydrodynamics of the multiphase-droplet the aim of this study is to create greater insight into the character of this transient-boiling process, for the first time. The sudden depressurization of a water column led to the rapid boiling of liquid propane droplets rising by buoyancy. During this millisecond boiling distinct stages were identified. Appropriate critical times for the transition between stages were defined by a simplified model, among these a novel criterion for the sudden pause in boiling caused by the engulfing liquid-film's collapse. Good agreement was found between these predicted time-points and measured changes in the boiling profile. This form of boiling, though being very rapid and sustaining high heat transfer rates, is still calm in nature, therefore, more predictable and widely applicable. Understanding this form of boiling suggests that the “design” of the boiling curve may be possible by setting the initial parameters.

Two-phase damping and interface surface area in tubes with vertical internal flow

2009 ◽  
Vol 25 (1) ◽  
pp. 178-204 ◽  
Author(s):  
C. Béguin ◽  
F. Anscutter ◽  
A. Ross ◽  
M.J. Pettigrew ◽  
N.W. Mureithi
Keyword(s):  
Surface Area ◽  
Internal Flow ◽  
Two Phase ◽  
Phase Damping ◽  
Interface Surface ◽  
Interface Surface Area

Estimation of Interfacial Area Concentration for Two-Phase Slug Flow From Dual-Probe Hot-Film Measurements

2003 ◽  
Author(s):  
G. Wang ◽  
C. Y. Ching
Keyword(s):  
Surface Area ◽  
Slug Flow ◽  
Synthesis Method ◽  
Gas Bubbles ◽  
Interfacial Area ◽  
Two Phase ◽  
Interfacial Area Concentration ◽  
Hot Film ◽  
Dual Probe ◽  
Taylor Bubbles

A relatively simple technique has been developed to estimate the interfacial area concentration (ai) of vertically upward gas-liquid slug flow from dual-probe hot-film anemometry measurements. The slug flow is modeled as a series of Taylor bubbles having a regular bullet-like shape separated by liquid slugs containing small spherical gas bubbles. The total interfacial area is the sum of the Taylor bubble surface area and the surface area of the bubbles in the liquid slugs. The ai is estimated from the mean diameter and local void fraction of the bubbles in the liquid slugs, and the length of the Taylor bubbles. These parameters are obtained through selective discrimination of the hot-film signals to separate the Taylor bubbles from the smaller gas bubbles in the liquid slugs. The important non-dimensional parameters that influence the interfacial area concentration are obtained using the synthesis method. A new correlation for ai for vertically-upward slug flow is developed based on the present measurements.

scholarly journals Oxygen Transfer Effects in a Two-Phase System of an Aqueous Phase and Liquid Perfluorochemical Subjected to Continuous Wave-Assisted Agitation in Disposable Bioreactor

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4381
Author(s):  
Kamil Wierzchowski ◽  
Paweł Sobieszuk ◽  
Maciej Pilarek
Keyword(s):  
Mass Transfer ◽  
Aqueous Phase ◽  
Oxygen Transfer ◽  
Continuous Wave ◽  
Interfacial Area ◽  
Immiscible Liquid ◽  
Phase System ◽  
Transfer Effects ◽  
Two Phase ◽  
Development Factor

Systems of two immiscible liquid phases—aqueous phase (i.e., distilled water (dH2O) or phosphate-buffered saline (PBS)) and liquid perfluorochemical (i.e., perfluorodecalin (PFD))—were subjected to wave-assisted agitation, i.e., oscillatory rocked, in a disposable bag-like container in a ReadyToProcess WAVETM25 bioreactor, to recognize oxygen transfer effects and effectivity of the surface aeration. According to the DoE methodology, values of the volumetric liquid-side mass transfer (kLa) coefficient for dH2O, PBS, dH2O-PFD, and PBS-PFD systems were determined for the whole range of operating parameters of the WAVE 25 bioreactor. A significantly higher maximal value of kLa was found for waving dH2O than for dH2O-PFD (i.e., 0.00460 s−1 vs. 0.00331 s−1, respectively) compared to more equal maximal values of kLa reached for PBS and PBS-PFD (0.00355 s−1 vs. 0.00341 s−1, respectively). The interface development factor (f) depended on the interfacial area a, and the enhancement factor (EPFD), depending on kLa, was introduced to quantitatively identify the mass transfer effects in the systems of waving two immiscible liquids. The phase of PFD was identified as the reservoir of oxygen. Dimensional correlations were proposed for the prediction of the kLa coefficient, in addition to the f and EPFD factors. The presented correlations, and the set of kLa values, can be directly applied to predict oxygen transfer effects reached under continuous oscillatory rocked systems containing aqueous phase and liquid perfluorochemical.

A numerical study of droplet splitting in branched T-shaped microchannel using the two-phase level-set method

2021 ◽  
Vol 13 (11) ◽  
pp. 168781402110454
Author(s):  
Mohammad Raad ◽  
Sajad Rezazadeh ◽  
Habib Jalili ◽  
Davod Abbasinezhad Fallah
Keyword(s):  
Pressure Gradient ◽  
Level Set Method ◽  
Level Set ◽  
Numerical Study ◽  
Immiscible Liquid ◽  
Length Ratio ◽  
Significant Feature ◽  
Two Phase ◽  
Droplet Splitting ◽  
Passive Technique

Droplet splitting as a significant feature of droplet-based microfluidic systems has been widely employed in biotechnology, biomedical engineering, tissue engineering, and it has been preferred over continuous flow systems. In the present paper, two-dimensional numerical simulations have been done to examine the asymmetrical droplet splitting process. The two-phase level set method (LSM) has been predicted to analyze the mechanism of droplet formation and droplet splitting in immiscible liquid/liquid two-phase flow in the branched T-junction microchannel. Governing equations on flow field have been discretized and solved using finite element-based COMSOL Multiphysics software (version 5.3a). Obtained numerical results were validated by experimental data reported in the literature which show acceptable agreement. The model was developed to simulate the mechanism of droplet splitting at the branched T-junction microchannel. This study provides a passive technique to asymmetrically split up microdroplets at the downstream T-junctions. The results show that outlet branches’ pressure gradient affects the droplet splitting. Specifically, it has been shown that the splitting ratio increases by increasing the length ratio, and equal droplet splitting can be achieved where the ratio is LL/ Lu = 1. We have used two outlet branches having the same width but different lengths to create the required pressure gradient. As the length ratio of the outlet branches increases, the diameter ratio increases as well.

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