Selective Freezing of a Dilute Salt Solution on a Cold Ice Surface

1984 ◽  
Vol 106 (2) ◽  
pp. 385-393 ◽  
Author(s):  
L. J. Fang ◽  
F. B. Cheung ◽  
J. H. Linehan ◽  
D. R. Pedersen
Keyword(s):  
Salt Solution ◽  
Solid Phase ◽  
Transient Heat Conduction ◽  
Phase Region ◽  
Transient Temperature ◽  
Two Phase ◽  
Transient Temperature Distribution ◽  
Ice Surface ◽  
Solid Liquid Interface ◽  
Solid Liquid

The growth of a solid–liquid, two-phase region during selective freezing of a dilute, eutectic-forming, salt solution over a subcooled ice slab is investigated experimentally and theoretically. The morphology of the two-phase region and the kinetics of the solid–liquid interface observed for a NaCl-H2O system are described photographically. The motion of the two-phase, liquidus front, recorded by a telescopic device that amplifies the local phenomena of the two-phase region, is presented along with the measured transient temperature distribution of the system. Based on the assumption that the solution element of the two-phase region is in local thermodynamic equilibrium with the solid phase, a similarity model is developed to predict the dependence of the freezing rate on various controlling parameters of the system. Transient heat conduction in the ice slab is also included in the model to study the effect of the wall. Comparison is made between the analytical and the experimental results and found to be good.

Analytical Modeling of Outward Solidification With Convective Boundary in Cylindrical Coordinates

2020 ◽  
Author(s):  
Minghan Xu ◽  
Saad Akhtar ◽  
Ahmad F. Zueter ◽  
Mahmoud A. Alzoubi ◽  
Agus P. Sasmito
Keyword(s):  
Moving Boundary ◽  
Two Phase ◽  
Convective Boundary ◽  
Interface Motion ◽  
Stefan Number ◽  
Melting Phenomenon ◽  
Approximate Analytical Solutions ◽  
Highly Nonlinear ◽  
Solid Liquid Interface ◽  
Solid Liquid

Abstract Solidification consists of three stages at macroscale: subcooling, freezing and cooling. Classical two-phase Stefan problems describe freezing (or melting) phenomenon initially not at the fusion temperature. Since these problems only define subcooling and freezing stages, an extension to characterize the cooling stage is required to complete solidification. However, the moving boundary in solid-liquid interface is highly nonlinear, and thus exact solution is restricted to certain domains and boundary conditions. It is therefore vital to develop approximate analytical solutions based on physically tangible assumptions, like a small Stefan number. This paper proposes an asymptotic solution for a Stefan-like problem subject to a convective boundary for outward solidification in a hollow cylinder. By assuming a small Stefan number, three temporal regimes and four spatial layers are considered in the asymptotic analysis. The results are compared with numerical method. Further, effects of Biot numbers are also investigated regarding interface motion and temperature profile.

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.

Microstructure Evolution of Ti-Al Peritectic System during the Initiated Stage of Directional Solidification

2007 ◽  
Vol 546-549 ◽  
pp. 1447-1450 ◽  
Author(s):  
Yan Qing Su ◽  
Chang Liu ◽  
Xin Zhong Li ◽  
Jing Jie Guo ◽  
Heng Zhi Fu
Keyword(s):  
Steady State ◽  
Directional Solidification ◽  
Microstructure Evolution ◽  
Aluminum Content ◽  
Solid Phase ◽  
Tial Alloys ◽  
Transient Stage ◽  
Set Up ◽  
Solid Liquid Interface ◽  
Solid Liquid

The microstructure evolution of Ti-Al peretectic system in transient stage and steady state in directional solidification was predicted via theoretical analysis. The solute distribution controlled by diffusion at and ahead the solid-liquid interface will determine whether the properitectic and peritectic phases can nucleate and grow ahead of the opposing solid phase. The formation of banding structure is possible in a certain composition range. At the steady state, a microstructure selection map was set up based on interface response function model. The microstructure of TiAl alloys with different aluminum content was studied with Bridgman directional solidification method. Some evidence in the experiment has been found to support the theoretical prediction.

An Inverse Finite Element Method for the Analysis of Stationary Arc Welding Processes

1986 ◽  
Vol 108 (4) ◽  
pp. 734-741 ◽  
Author(s):  
Y. F. Hsu ◽  
B. Rubinsky ◽  
K. Mahin
Keyword(s):  
Finite Element ◽  
Arc Welding ◽  
Computer Code ◽  
Transient Temperature ◽  
Work Piece ◽  
Transient Temperature Distribution ◽  
Interpolation Procedure ◽  
Solid Region ◽  
Solid Liquid Interface ◽  
Welding Processes

An inverse finite element computer code was developed to facilitate the experimental analysis of two-dimensional stationary arc welding processes. The method uses transient temperature data from thermocouples imbedded in the solid region of the work piece to determine through a Newton–Raphson interpolation procedure the transient position of the solid–liquid interface and the transient temperature distribution in the solid region of the work piece. The accuracy of the method was demonstrated through comparison with results obtained with a direct finite element code and through comparison with experiments.

Studies on Heat Transfer From a Vertical Cylinder, With or Without Fins, Embedded in a Solid Phase Change Medium

1985 ◽  
Vol 107 (1) ◽  
pp. 44-51 ◽  
Author(s):  
B. Kalhori ◽  
S. Ramadhyani
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Natural Convection ◽  
Solid Phase ◽  
Vertical Cylinder ◽  
Interface Shape ◽  
Fusion Temperature ◽  
Total Heat Transfer ◽  
Solid Liquid Interface ◽  
Solid Liquid

An experimental investigation of melting and cyclic melting and freezing around a vertical cylinder is reported. The studies encompass two cases: a plain vertical cylinder, and a vertical cylinder with fins. In the melting studies, the total heat transfer from the cylinder was measured as a function of time. In addition, measurements have been made of the solid-liquid interface shape after various melting times. In these studies, the solid phase was initially isothermal and either at its fusion temperature or subcooled below the fusion point. The experiments reveal the important influence of natural convection in the liquid phase in both unfinned and finned situations. Subcooling of the solid phase is observed to strongly inhibit heat transfer in the unfinned situation. In the experiment on cyclic melting and freezing, subcooling of the solid phase is once again found to have an important effect on the unfinned situation. Heat transfer from the finned cylinder is much less affected by solid-phase subcooling. All the experiments were performed with 99 percent pure n-eicosane paraffin.

scholarly journals The Simulation of the Preparation of the Ingot With Liquid Core

2021 ◽  
Author(s):  
yongqiang wu ◽  
Zhi-ren Sun ◽  
Kaikun Wang
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Liquid Phase ◽  
Solid Phase ◽  
Liquid Core ◽  
Phase Region ◽  
Simulation Results ◽  
Solid Liquid ◽  
Deform 3D ◽  
Ultra High Temperature

Abstract During the preparation of the ingot with liquid core in the early stage, the finite element models of the solidification and the ultra-high temperature demoulding were established in DEFORM-3D. The thermophysical properties of ASSAB 718 with the variations of C, Mn and Cr were calculated in JMatPro®. The material database was imported into DEFORM-3D. Through the analysis of the finite element simulation results, we obtained the influence of three main elements C, Mn and Cr contents on the size of the solid-phase region, the liquid-phase region and the solid-liquid two-phase region in the ingot. We optimized the composition of the material to get a wide solid-liquid phase range. The high carbon, the medium manganese and the high chromium contents were beneficial to form the liquid core. Based on the method of the solidification time, the algorithm was programmed by the python language. We analyzed the influence of the three elements C, Mn, and Cr on the concentration distribution based on the temperature field data, which were obtained by DEFORM-2D after the solidification and the ultra-high temperature demoulding. According to the simulation results, we found that the region prone to negative segregation.

scholarly journals Influence of Blade Type on the Flow Structure of a Vortex Pump for Solid-Liquid Two-Phase Flow

Machines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 353
Author(s):  
Hui Quan ◽  
Yanan Li ◽  
Lei Kang ◽  
Xinyang Yu ◽  
Kai Song ◽  
...  
Keyword(s):  
Flow Structure ◽  
Liquid Flow ◽  
Single Phase ◽  
Solid Phase ◽  
Internal Flow ◽  
Phase Flow ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Vortex Pump ◽  
Solid Liquid

Vortex pumps have good non-clogging performance owing to their impellers being retracted into retraction cavities, but they are much less efficient than ordinary centrifugal pumps. In this paper, numerical simulations were performed on a model of the 150WX200-20 vortex pump for four different blade types, and the influence of blade structure on pump performance was determined. The simulations revealed the existence of axial vortices in the flow passage between the blades in the impeller region. The geometric characteristics of these axial vortices were more regular in two-phase solid-liquid flow than single-phase liquid flow. The presence of the solid phase reduced the vortex strength compared with the single-phase flow and suppressed the increase in size of the secondary circulation vortex. It was found, however, that the blade shape had a greater influence on the circulating flow than the presence of the solid phase. The flow state of the medium flowing out of the impeller domain had a direct effect on the circulating flow with this effect being related to the law governing the flow of the medium in the flow channel between the blades. It was found that the performance of a front-bent blade was the best and that of a curved blade the worst. This influence of blade type on the internal flow structure was used to further explain the relationship between the internal flow structure and the external characteristics of the vortex pump, the understanding of which is crucial for blade selection and hydraulic optimization.

Influence of vibration on grain size and degree of grain refinement in mild steel weldments

1993 ◽  
Vol 8 (9) ◽  
pp. 2228-2230 ◽  
Author(s):  
S.P. Tewari
Keyword(s):  
Grain Size ◽  
Mild Steel ◽  
Grain Refinement ◽  
Solid Phase ◽  
Steel Plates ◽  
Lower Amplitude ◽  
Experimental Findings ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Fast Removal

Mild steel plates were welded under stationary and dynamic (longitudinal and transverse vibration) conditions. The frequency and amplitude ranges selected were 0 Hz to 300 Hz and 0 μm to 30 μm, respectively. It has been observed on the basis of experimental findings that vibration, in general, reduces the grain size of the weldment, and this reduction is appreciable at a lower amplitude of vibration. This may be due to the lower energy required for nucleation of the solid phase. Fast removal of latent heat of solidification from the solid liquid interface plays a significant part in the grain refinement under vibration.

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.

Submicron Conductor Array Fabricated from a Recrystallized Eutectic Thin Film

1982 ◽  
Vol 13 ◽  
Author(s):  
H. E. Cline
Keyword(s):  
Thin Film ◽  
Eutectic Alloy ◽  
Solidification Rate ◽  
Eutectic Structure ◽  
Alloy Thin Film ◽  
Directionally Solidified ◽  
Two Phase ◽  
Glass Substrates ◽  
Solid Liquid Interface ◽  
Solid Liquid

ABSTRACTA submicron conductor array was fabricated without using lithography by selectively etching a recrystallized A1-A12Cu eutectic alloy thin film. The 2 micron thick eutectic films were deposited on glass substrates and directionally solidified with both a quartz-iodine lamp and a scanning laser at rates between .0016 and .14 cm/sec. The resulting structure consisted of alternate parallel stripes of the two eutectic phases with a spacing between .5 and 4 microns that was controlled by the solidification rate. An array of submicron Al- rich conductors was fabricated by selectively etching away the Al2 Cu phase. At solidification rates greater than .004 cm/sec using the lamp heater the solid-liquid interface became non-planar while with the laser the structure was well alligned at the highest rates used, .14 cm/sec. At the maximum theoretical solidification rate that produces a two phase aligned eutectic structure the width of the Al wires would be 100A.

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