scholarly journals Thermodynamic acceleration of two-phase layered flows in channels with permeable walls of MGD-generators

2021 ◽  
Vol 2131 (2) ◽  
pp. 022059
Author(s):  
K K Kim
Keyword(s):  
Liquid Metal ◽  
Side Surface ◽  
Channel Length ◽  
Maximum Efficiency ◽  
Two Phase ◽  
Piston Speed ◽  
Permeable Walls ◽  
Injection Coefficient ◽  
Frictional Forces ◽  
The One

Abstract When creating MHD (Magnetohydrodynamic) alternating current generators using liquid-metal working body, the latter is accelerated by piston method, in which the working body is a periodic structure of alternating zones of liquid metal (pistons) and zones of compressed gas, the latter is accelerated liquid-metal pistons. This raises the form stability problem for liquid metal pistons. Viscous frictional forces generated inside the pistons lead to the destruction of the pistons and significantly reduce the efficiency of the MHD unit. One solution is to use gas-permeable walls of the channels of MHD-generators, through the pores of which gas is injected. In this way, the piston flow is isolated from the side surface of the channel by the penetrating gas in the channel cavity. As a result, friction losses are drastically reduced. At the final values of the One solution is to use gas-permeable walls of the channels of MHD-generators, through the pores of which gas is injection coefficients, (? ≥ 0.03)the friction practically disappears. With the channel length determined by the coordinate of the maximum piston speed, 92% of the current marginal efficiency values can be achieved. The maximum efficiency of the runaway channel can be achieved by selecting the optimal value of the air injection coefficient. The operation of the devices commutating the injected gas must ensure that there is an injection in an area that is no more than twice the length of the piston.

scholarly journals Solar Collectors Based оn Copper Two-Phase Thermosyphons

2020 ◽  
Vol 63 (5) ◽  
pp. 472-484
Author(s):  
V. I. Marynenko ◽  
V. S. Kulynych
Keyword(s):  
Solar Energy ◽  
Solar Collector ◽  
Energy Systems ◽  
Heat Pipes ◽  
Maximum Efficiency ◽  
Solar Collectors ◽  
Two Phase ◽  
Initial Water ◽  
The One ◽  
Solar Rays

Thermosyphons and heat pipes offer great opportunities for creating pas sive heat and mass transfer systems. Various design solutions using heat pipes (thermosyphons) in solar energy systems are known. Solar energy is one of the promising energy sources, a step towards reducing dependence on other energy resources. To date, there is already an industrial production of solar collectors based on thermosyphons (heat pipes). In solar collectors, the use of thermosyphons (heat pipes) makes it possible to simplify the assembly of the structure, ensures its high modularity, maintainability and reliability. In the course of research, the authors have developed and justified the design of a solar collector based on thermosyphons fixed on panels that absorb solar rays. In order to analyze the efficiency of the solar collector based on two-phase copper thermosyphons, two models of solar collectors were created, viz. the one with a flat absorbing panel and the one with a cylindrical absorbing panel. The areas of the absorbing surfaces were the same. Both models were studied by the method of thermophysycal experiment. The results of studies of the effectiveness of the above-mentioned solar collectors have been obtained. The efficiency of the solar collector based on a copper two-phase thermosyphon, which is fixed on a cylindrical absorbing panel is 2–5 % more than the efficiency of the solar collector based on a copper two-phase thermosyphon, which is fixed on a flat absorbing panel. The maximum efficiency value obtained at low initial water temperatures for solar collectors with a cylindrical and flat absorbing surface was 60 %.

scholarly journals Experimental and Numerical Investigation of Gas-Liquid Metal Two-Phase Flow Pumping

2021 ◽  
pp. 100092
Author(s):  
Josh Rosettani ◽  
Wael Ahmed ◽  
Philip Geddis ◽  
Lijun Wu ◽  
Bruce Clements
Keyword(s):  
Liquid Metal ◽  
Numerical Investigation ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase

scholarly journals Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe

2008 ◽  
Vol 10 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Roch Plewik ◽  
Piotr Synowiec ◽  
Janusz Wójcik
Keyword(s):  
Cfd Simulation ◽  
Fluidised Bed ◽  
Cfd Simulations ◽  
Two Phase ◽  
Hydraulic Behaviour ◽  
Hydraulic Conditions ◽  
The One ◽  
Cfd Method ◽  
Multi Phase ◽  
The Ideal

Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe The hydrodynamics in fluidized-bed crystallizers is studied by CFD method. The simulations were performed by a commercial packet of computational fluid dynamics Fluent 6.x. For the one-phase modelling (15), a standard k-ε model was applied. In the case of the two-phase flows the Eulerian multi-phase model with a standard k-ε method, aided by the k-ε dispersed model for viscosity, has been used respectively. The collected data put a new light on the suspension flow behaviour in the annular zone of the fluidised bed crystallizer. From the presented here CFD simulations, it clearly issues that the real hydraulic conditions in the fluidised bed crystallizers are far from the ideal ones.

scholarly journals Observation and control of the weak topological insulator state in ZrTe5

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Peng Zhang ◽  
Ryo Noguchi ◽  
Kenta Kuroda ◽  
Chun Lin ◽  
Kaishu Kawaguchi ◽  
...  
Keyword(s):  
Band Gap ◽  
Topological Insulator ◽  
Spin Current ◽  
Side Surface ◽  
Quantum Spin ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Dirac Semimetal ◽  
Topological States ◽  
The One ◽  
And Control

AbstractA quantum spin Hall (QSH) insulator hosts topological states at the one-dimensional (1D) edge, along which backscattering by nonmagnetic impurities is strictly prohibited. Its 3D analogue, a weak topological insulator (WTI), possesses similar quasi-1D topological states confined at side surfaces. The enhanced confinement could provide a route for dissipationless current and better advantages for applications relative to strong topological insulators (STIs). However, the topological side surface is usually not cleavable and is thus hard to observe. Here, we visualize the topological states of the WTI candidate ZrTe5 by spin and angle-resolved photoemission spectroscopy (ARPES): a quasi-1D band with spin-momentum locking was revealed on the side surface. We further demonstrate that the bulk band gap is controlled by external strain, realizing a more stable WTI state or an ideal Dirac semimetal (DS) state. The highly directional spin-current and the tunable band gap in ZrTe5 will provide an excellent platform for applications.

scholarly journals On the Two-phase Fractional Stefan Problem

2020 ◽  
Vol 20 (2) ◽  
pp. 437-458 ◽  
Author(s):  
Félix del Teso ◽  
Jørgen Endal ◽  
Juan Luis Vázquez
Keyword(s):  
Free Boundary ◽  
Stefan Problem ◽  
Free Boundary Problems ◽  
Classical Problem ◽  
Nonlocal Diffusion ◽  
Two Phase ◽  
Boundary Problems ◽  
Numerical Studies ◽  
The One ◽  
Evolution Type

AbstractThe classical Stefan problem is one of the most studied free boundary problems of evolution type. Recently, there has been interest in treating the corresponding free boundary problem with nonlocal diffusion. We start the paper by reviewing the main properties of the classical problem that are of interest to us. Then we introduce the fractional Stefan problem and develop the basic theory. After that we center our attention on selfsimilar solutions, their properties and consequences. We first discuss the results of the one-phase fractional Stefan problem, which have recently been studied by the authors. Finally, we address the theory of the two-phase fractional Stefan problem, which contains the main original contributions of this paper. Rigorous numerical studies support our results and claims.

Study of CFD Modeling of Performance for Classification

2012 ◽  
Vol 516-517 ◽  
pp. 784-789
Author(s):  
Wei Cao ◽  
Ying Fang ◽  
De Xiang Li
Keyword(s):  
Simulation Experiment ◽  
Particle Trajectory ◽  
Phase Particle ◽  
Theoretical Perspective ◽  
Cfd Modeling ◽  
Optimized Design ◽  
Two Phase ◽  
Ansys Cfx ◽  
The One ◽  
Classification Efficiency

The numerical simulation in the classification has been used in ANSYS CFX 10.0. We described the different flow fields within the classification in accordance with the one-phase simulation experiment, which provided a new theoretical perspective for optimized design on classification. At the same time, the classification efficiency was predicted by simulation for two phase particle trajectory. This will lay a foundation for improving classification efficiency.

Suitability of Eutectic Field’s Metal for Use in an Electromagnetohydrodynamically-Enhanced Experimental Two-Phase Flow Loop

2012 ◽  
Author(s):  
A. Lipchitz ◽  
Lilian Laurent ◽  
G. D. Harvel
Keyword(s):  
Liquid Metal ◽  
Two Phase Flow ◽  
Nuclear Reactors ◽  
Liquid Metals ◽  
Metal Flow ◽  
Phase Flow ◽  
Laboratory Setting ◽  
Flow Loop ◽  
Fast Reactors ◽  
Two Phase

Several Generation IV nuclear reactors, such as sodium fast reactors and lead-bismuth fast reactors, use liquid metal as a coolant. In order to better understand and improve the thermal hydraulics of liquid metal cooled GEN IV nuclear reactors liquid metal flow needs to be studied in experimental circulation loops. Experimental circulation loops are often located in a laboratory setting. However, studying liquid metal two phase flow in laboratory settings can be difficult due to the high temperatures and safety hazards involved with traditional liquid metals such as sodium and lead-bismuth. One solution is to use a low melt metal alloy that is as benign as reasonably achievable. Field’s metal is a eutectic alloy of 51% Indium, 32.5% Bismuth and 16.5% Tin by weight and has a melting point of 335K making it ideal for use in a laboratory setting. A study is undertaken to determine its suitability to use in a two-phase experimental flow loop enhanced by magnetohydrodynamic forces. The study investigated its reactivity with air and water, its ability to be influenced by magnetic fields, its ability to flow, and its ease of manufacture. The experiments melted reference samples of Field’s metal and observed its behaviour in a glass beaker, submerged in water and an inclined stainless steel pipe. Then Field’s metal was manufactured in the laboratory and compared to the sample using the same set of experiments and standards. To determine Field’s metal degree of magnetism permanent neodymium magnets were used. Their strength was determined using a Gaussmeter. All experiments were recorded using a COHU digital camera. Image analysis was then performed on the video to determine any movements initiated by the magnetic field forces. In conclusion, Field’s metal is more than suitable for use in experimental settings as it is non-reactive, non-toxic, simple to manufacture, easy to use, and responds to a magnetic force.

scholarly journals Gallstone ileus resulting in strong intestinal obstruction

1995 ◽  
Vol 113 (1) ◽  
pp. 721-725
Author(s):  
Israel Szajnbok ◽  
Fernando Lorenzi ◽  
Aldo Junqueira Rodrigues Jr. ◽  
Luis Fernando Correa Zantut ◽  
Renato Sérgio Poggetti ◽  
...  
Keyword(s):  
Intestinal Obstruction ◽  
Gallstone Ileus ◽  
Ileocecal Valve ◽  
Mortality Rates ◽  
Degenerative Diseases ◽  
Two Phase ◽  
Therapy Decision ◽  
Biliary Calculus ◽  
The One ◽  
Elder People

Mechanic intestinal obstruction, caused by the passage of biliary calculus from vesicle to intestine, through fistulization, although not frequent, deserve study due to the morbi-mortality rates. Incidence in elder people explains the association with chronic degenerative diseases, increasing complexity in terms of therapy decision. Literature discusses the need and opportunity for the one or two-phase surgical attack of the cholecystenteric fistule, in front of the resolution on the obstructive urgency and makes reference to Gallstone Ileus as an exception for strong intestinal obstruction. The more frequent intestinal obstruction observed is when it occurs a Gallstone Ileus impacting in terms of ileocecal valve. The authors submit a Gallstone Ileus manifestation as causing strong intestinal obstruction, discussing aspects regarding diagnostic and treatment.

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