Crystallization of liquids in the vicinity of a solid

1981 ◽  
Vol 34 (1) ◽  
pp. 1
Author(s):  
JE Lane ◽  
TH Spurling
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Solid Phase ◽  
Adsorbed Layer ◽  
Liquid Interface ◽  
Spherically Symmetric ◽  
Present Evidence ◽  
Ensemble Monte Carlo ◽  
Solid Liquid Interface ◽  
Solid Liquid

We present evidence, gained from grand ensemble Monte Carlo simulations of the solid/liquid interface, that an adsorbed layer of spherically symmetric liquid particles can have a crystal-like structure even if the solid phase is structureless.

Transient Freezing of Liquids in Forced Flow Inside Circular Tubes

1969 ◽  
Vol 91 (3) ◽  
pp. 385-389 ◽  
Author(s):  
M. N. O¨zis¸ik ◽  
J. C. Mulligan
Keyword(s):  
Solid Phase ◽  
Freezing Temperature ◽  
Local Heat ◽  
Liquid Interface ◽  
Forced Flow ◽  
Transfer Rates ◽  
Tube Wall Temperature ◽  
Temperature Constant ◽  
Solid Liquid Interface ◽  
Solid Liquid

The transient freezing of a liquid flowing inside a circular tube is investigated analytically under the assumption of a constant tube wall temperature which is lower than the freezing temperature, constant properties, a slug-flow velocity profile and quasisteady state heat conduction in the solid phase. The variation of the local heat flux and the profile of the solid-liquid interface during freezing has been determined as a function of time and position along the tube. The analysis produced steadystate heat transfer rates and profiles for the solid-liquid interface which agreed well with experiments.

scholarly journals Numerical Simulation of Solidification of Colloids Inside a Differentially Heated Cavity

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Yousef M. F. EL Hasadi ◽  
J. M. Khodadadi
Keyword(s):  
Solid Phase ◽  
Colloidal Suspension ◽  
Concentration Field ◽  
Liquid Interface ◽  
Thermosolutal Convection ◽  
Alumina Nanoparticles ◽  
Convection Cell ◽  
Fluid Mixture ◽  
Solid Liquid Interface ◽  
Solid Liquid

Development of the solid–liquid interface, distribution of the particle concentration field, as well as the development of thermosolutal convection during solidification of colloidal suspensions in a differentially heated cavity are investigated. The numerical model is based on the one-fluid mixture approach combined with the single-domain enthalpy porosity model for phase change, and it is implemented in fluent software package. The linear dependence of the liquidus and solidus temperatures with the concentration of the nanoparticles was assumed. A colloidal suspension consisting of water and copper or alumina nanoparticles were considered. In the current investigation, the nanoparticle size selected was 5 and 2 nm. The suspension was solidified unidirectionally inside a square differentially heated cavity that was cooled from the left side. It was found that the solid–liquid interface changed its morphology from a planar shape to a dendritic one as the solidification process proceeds in time, due to the constitutional supercooling that resulted from the increased concentration of particles at the solid–liquid interface rejected from the crystalline phase. Initially, the flow consisted of two vortices rotating in opposite directions. However, at later times, only one counter clockwise rotating cell survived. Changing the material of the particle to alumina resulted in crystallized phase with a higher concentration of particles. If it is compared to that of the solid phase resulted from freezing the copper–water colloidal suspension. Decreasing the segregation coefficient destabilizes the solid–liquid interface and increases the intensity of the convection cell with respect to that of the case of no particle rejection. At slow freezing rates, the resulting crystal phase consisted of lower particle content compared to the case of higher freezing rate.

scholarly journals The combined effects of shear and buoyancy on phase boundary stability

2019 ◽  
Vol 868 ◽  
pp. 648-665 ◽  
Author(s):  
S. Toppaladoddi ◽  
J. S. Wettlaufer
Keyword(s):  
Shear Flow ◽  
Solid Phase ◽  
Liquid Interface ◽  
Flow Instabilities ◽  
Flow Strength ◽  
Buoyancy Driven Flows ◽  
The Stability ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Boundary Stability

We study the effects of externally imposed shear and buoyancy driven flows on the stability of a solid–liquid interface. A linear stability analysis of shear and buoyancy-driven flow of a melt over its solid phase shows that buoyancy is the only destabilizing factor and that the regime of shear flow here, by inhibiting vertical motions and hence the upward heat flux, stabilizes the system. It is also shown that all perturbations to the solid–liquid interface decay at a very modest shear flow strength. However, at much larger shear-flow strength, where flow instabilities coupled with buoyancy might enhance vertical motions, a re-entrant instability may arise.

Numerical Simulation of Solidification of Colloidal Suspensions Inside a Differentially-Heated Cavity

2013 ◽  
Author(s):  
Yousef M. F. El Hasadi ◽  
J. M. Khodadadi
Keyword(s):  
Solid Phase ◽  
Colloidal Suspension ◽  
Concentration Field ◽  
Colloidal Suspensions ◽  
Liquid Interface ◽  
Alumina Nanoparticles ◽  
Convection Cell ◽  
Fluid Mixture ◽  
Solid Liquid Interface ◽  
Solid Liquid

Development of the solid-liquid interface, distribution of the particle concentration field, as well as the development of thermo-solutal convection during solidification of colloidal suspensions in a differentially-heated cavity is investigated. The numerical model is based on the one-fluid-mixture approach combined with the single-domain enthalpy-porosity model for phase change. The linear dependence of the liquidus concentration of the nanoparticles was assumed. A colloidal suspension consisting of water and copper, and alumina nanoparticles were considered. In the current investigation, the nanoparticle size selected was 2 nm. The suspension was solidified unidirectionally inside a square differentially-heated cavity that was cooled from the left side. It was found that the solid-liquid interface changed its morphology from a planar shape to a dendritic one as the solidification process proceeds in time, due to the constitutional supercooling that resulted from the increased concentration of particles at the solid-liquid interface rejected from the crystalline phase. Initially, the flow consisted of two vortices rotating in opposite directions. However, at later times only one counter clockwise rotating cell survived. Changing the material of the particle to alumina results in crystallized phase with a higher concentration of particles if it is compared to that of the solid phase resulted from freezing the copper-water colloidal suspension. Decreasing the segregation coefficient destabilize the solid-liquid interface, and increase the intensity of the convection cell with respect to that of the case of no particle rejection. At slow freezing rates, the crystal phase resulted consisted of lower particle content if it is compared to that resulted from higher freezing rate.

Characterization of the adsorption properties of a phosphorylated kraft lignin-based polymer at the solid/liquid interface by the QCM-D approach

Holzforschung ◽  
2016 ◽  
Vol 70 (10) ◽  
pp. 937-945 ◽  
Author(s):  
Wenlong Xiong ◽  
Xueqing Qiu ◽  
Ruisheng Zhong ◽  
Dongjie Yang
Keyword(s):  
Self Assembly ◽  
Uv Spectroscopy ◽  
Adsorbed Layer ◽  
Kraft Lignin ◽  
Liquid Interface ◽  
Inorganic Materials ◽  
Layer By Layer ◽  
Adsorption Characteristics ◽  
Solid Liquid Interface ◽  
Solid Liquid

Abstract Phosphorylated kraft lignin (PKL), a novel lignin polymer, has potential application in the preparation and modification of inorganic materials. In this article, the adsorption characteristics of PKL at the solid/liquid interface were investigated under different pH conditions. Quartz crystal microbalance combined with dissipation monitoring (QCM-D), UV spectroscopy, and atomic force microscopy (AFM) were applied for monitoring the adsorption. The adsorbed amount of PKL gradually decreased as a function of pH increment on the gold covered QCM-D crystals, which were pretreated with an adsorbed layer of poly(diallyldimethylammonium chloride) (PDAC). This was also the case for quartz slide substrates pretreated with PKL/PDAC multilayers by the method relying on the layer-by-layer (LBL) electrostatic self-assembly. The hydrophobicity of adsorbed PKL films increased with increasing pH from 3 to 12. In the course of this process, the adsorption morphology changed from a compact rigid state to a less compact soft state. Under acidic conditions, the adsorption is governed mainly by cation-π interaction between PKL and PDAC, and the adsorption configuration is mushroom-like. Under neutral and alkaline conditions, the cation-π interaction is less relevant owing to the longer distances between the anionic groups in PKL and the cation in PDAC. This causes stretching of the molecular chains in PKL, while the adsorption configuration changes to a planar pancake structure so that the electrostatic interaction dominates. The knowledge on adsorption characteristics of PKL at different pH values is helpful to prepare some lignin-based composite materials.

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