Towards a theory of directional solidification in the presence of a two-phase zone with intense convection in a liquid layer

2020 ◽  
Author(s):  
Dmitri V. Alexandrov ◽  
Nikita K. Goltyakov ◽  
Alexander A. Ivanov
Keyword(s):  
Directional Solidification ◽  
Liquid Layer ◽  
Phase Zone ◽  
Two Phase

Fabrication of ZA Alloy Rods by Continuous Casting with Heated Mold

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1503-1509
Author(s):  
Ma Ying ◽  
Hao Yuan ◽  
Feng Yun Yan ◽  
Hong Jun Liu ◽  
Chang Min Suh
Keyword(s):  
Continuous Casting ◽  
Directional Solidification ◽  
Surface Quality ◽  
Alloy Composition ◽  
Pressure Head ◽  
Outlet Temperature ◽  
Casting Method ◽  
Phase Zone ◽  
Two Phase

The continuous directional solidification technique of 5 kinds of special ZA alloys with eutectic, eutectoid and peritectic transformations under the condition of continuous casting by heated mold was studied. The optimum fitting range of technique factors in each alloy is found. The results show that the operation of guiding ingot is the key of the technique to produce directional solidification ZA alloy line by heated mold in continuous casting method. Outlet temperature, pulling speed, cooling condition, alloy composition and pressure head have direct influences on the surface quality of ingot. There is a balance between heat and force in the two-phase zone of solid and liquid. Only adjusting technique parameters with the balance and keeping a good place of the interface between solid and liquid, can the smooth ZA alloy line be continuously pulled out.

Gas-Water Flow Behaviour During Mutual Displacement in Porous Media

2017 ◽  
Vol 10 (1) ◽  
pp. 13-22
Author(s):  
Renyi Cao ◽  
Junjie Xu ◽  
Xiaoping Yang ◽  
Renkai Jiang ◽  
Changchao Chen
Keyword(s):  
Porous Media ◽  
Relative Permeability ◽  
Gas Storage ◽  
Fluid Distribution ◽  
Water Displacement ◽  
Phase Zone ◽  
Two Phase ◽  
Flow Process ◽  
Single Well ◽  
Mutual Displacement

During oilfield development, there exist multi-cycle gas–water mutual displacement processes. This means that a cycling process such as water driving gas–gas driving water–water driving gas is used for the operation of injection and production in a single well (such as foam huff and puff in single well or water-bearing gas storage). In this paper, by using core- and micro-pore scales model, we study the distribution of gas and water and the flow process of gas-water mutual displacement. We find that gas and water are easier to disperse in the porous media and do not flow in continuous gas and water phases. The Jamin effect of the gas or bubble becomes more severe and makes the flow mechanism of multi-cycle gas–water displacement different from the conventional water driving gas or gas driving water processes. Based on experiments of gas–water mutual displacement, the changing mechanism of gas–water displacement is determined. The results indicate that (1) after gas–water mutual displacement, the residual gas saturation of a gas–water coexistence zone becomes larger and the two-phase zone becomes narrower, (2) increasing the number of injection and production cycles causes the relative permeability of gas to increase and relative permeability for water to decrease, (3) it becomes easier for gas to intrude and the invaded water becomes more difficult to drive out and (4) the microcosmic fluid distribution of each stage have a great difference, which caused the two-phase region becomes narrower and effective volume of gas storage becomes narrower.

scholarly journals Time-resolved PIV measurements of a deflected submerged jet interacting with liquid-gas and liquid-liquid interfaces

2021 ◽  
Author(s):  
Stefan Puttinger ◽  
Mahdi Saeedipour
Keyword(s):  
Liquid Layer ◽  
Large Scale ◽  
Free Surface Flow ◽  
Industrial Applications ◽  
Liquid Pool ◽  
Surface Flow ◽  
Two Phase ◽  
Time Resolved ◽  
Submerged Jet ◽  
Major Interest

AbstractThis paper presents an experimental investigation on the interactions of a deflected submerged jet into a liquid pool with its above interface in the absence and presence of an additional lighter liquid. Whereas the former is a free surface flow, the latter mimics a situation of two stratified liquids where the liquid-liquid interface is disturbed by large-scale motions in the liquid pool. Such configurations are encountered in various industrial applications and, in most cases, it is of major interest to avoid the entrainment of droplets from the lighter liquid into the main flow. Therefore, it is important to understand the fluid dynamics in such configurations and to analyze the differences between the cases with and without the additional liquid layer. To study this problem, we applied time-resolved particle image velocimetry experiments with high spatial resolution. A detailed data analysis of a small layer beneath the interface shows that although the presence of an additional liquid layer stabilizes the oscillations of the submerged jet significantly, the amount of kinetic energy, enstrophy, and velocity fluctuations concentrated in the proximity of the interface is higher when the oil layer is present. In addition, we analyze the energy distribution across the eigenmodes of a proper orthogonal distribution and the distribution of strain and vortex dominated regions. As the main objective of this study, these high-resolution time-resolved experimental data provide a validation platform for the development of new models in the context of the volume of fluid-based large eddy simulation of turbulent two-phase flows.

Heat Transfer in Porous Media Heated From Above With Evaporation, Condensation, and Capillary Effects

1983 ◽  
Vol 105 (3) ◽  
pp. 485-492 ◽  
Author(s):  
K. S. Udell
Keyword(s):  
Stable State ◽  
Superheated Liquid ◽  
Phase Zone ◽  
Two Phase ◽  
Water Steam ◽  
Zone Length ◽  
Compressed Liquid ◽  
Pressure Lowering ◽  
Darcy’S Equations ◽  
Convection Dominated

Heat and mass transfer characteristics of a sand-water-steam system heated at the top and cooled at the bottom were studied. It was found that at steady-state conditions the system segregated into three regions. The top region was conduction-dominated with the voids containing a stationary superheated steam. The middle region was convection-dominated, nearly isothermal, and exhibited an upward flow of the liquid by capillary forces and a downward flow of steam due to a slight pressure gradient. The bottom portion contained a stationary compressed liquid and was also conduction dominated. The length of the two-phase convection zone was evaluated through the application of Darcy’s equations for two-phase flow and correlations of relative permeabilities and capillary pressure data. The model was in excellent agreement with the observed results, predicting a decreasing two-phase zone length with increasing heat flux. The thermodynamics of the two-phase zone were also analyzed. It was found that the vapor phase was in a superheated state as described by the Kelvin equation for vapor pressure lowering. Also, it was evident that the liquid must also be superheated for thermodynamic equilibrium to result. A stability analysis demonstrated that the superheated liquid can exist in an unconditionally stable state under conditions typical of porous systems. The degree of liquid superheat within the two-phase zone of these experiments was obtained.

Effect of RE on Performance of Semi-Solid AlSi7 Alloy

2010 ◽  
Vol 426-427 ◽  
pp. 581-584 ◽  
Author(s):  
Rong Xi Yi ◽  
Shi Kun Xie ◽  
Xiao Qiu Zheng ◽  
Yong Ping Ai
Keyword(s):  
Phase Zone ◽  
Two Phase ◽  
Semi Solid ◽  
Solid Liquid ◽  
Different Content ◽  
Zone Temperature

The semi-solid slurry of AlSi7 alloy was prepared by near-liquids cast processing. The effects of different content of RE on the cast performance and the semi-solid remelting performance in AlSi7 alloy was researched. The results indicated that adding RE will widen the AlSi7 alloy solid-liquid two-phase zone temperature and refine the grains, silicon will obvious metamorphoses. The best amount of RE is about 0.5%. Its semi-solid remelting organization is equilateral globular grains.

Solidification with a quasiequilibrium two-phase zone

2001 ◽  
Vol 49 (5) ◽  
pp. 759-764 ◽  
Author(s):  
D.V. Alexandrov
Keyword(s):  
Phase Zone ◽  
Two Phase

scholarly journals Precise Determination of Liquid Layer Thickness with Downward Annular Two-Phase Gas-Very Viscous Liquid Flow

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6529
Author(s):  
Krystian Czernek ◽  
Stanisław Witczak
Keyword(s):  
Viscous Liquid ◽  
Liquid Layer ◽  
Liquid Flow ◽  
Liquid Films ◽  
Measuring System ◽  
Image Analysis System ◽  
Oil Viscosity ◽  
Two Phase ◽  
Study Results

The paper presents the characteristics of the original optoelectronic system for measuring the values of hydrodynamics of two-phase downward gas-very viscous liquid flow. The measurement methods and results of the research on selected values describing gas–oil two-phase flow are presented. The study was conducted in vertical pipes with diameters of 12.5, 16, 22, and 54 mm. The research was conducted with the superficial velocities of air jg = 0–29.9 m/s and oil jl = 0–0.254 m/s, which corresponded to the values of gas stream density gg = (0–37.31) kg/(m2s) and of liquid gl = (0.61–226.87) kg/(m2s), in order to determine the influence of air and oil streams on the character of liquid films. The variations in oil viscosity were applied in the range ηl = (0.055–1.517) Pas. The study results that were obtained with optical probes along with computer image analysis system revealed vast research opportunities in terms of the identification of gas–liquid two-phase downward flow structures that were generated as well as the determination of the thickness of liquid film with various level of interfacial surface area undulation. The designed and constructed proprietary measuring system is also useful for testing the liquid layer by determining the parameters of the resulting waves. It is considered that the apparatus system that is presented in the article is the most effective in examining the properties of liquid layers of oil and other liquids with low electrical conductivity and a significant degree of monochromatic light absorption. In view of noninvasive technique of measuring characteristic values of liquid films being formed, the above measuring system is believed to be very useful for industry in the diagnostics of the apparatus employing such flows.

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