Showing papers on "Liquid metal published in 1981"
TL;DR: In this paper, the authors calculate the difference in the surface potentials between the free surface of a liquid metal and the same metal in an ideally polarizable interface at the point of zero charge, due to the deformation of the electronic cloud of the metal by the solvent molecules.
97 citations
60 citations
TL;DR: In this article, an electron-ion plasma model is examined against experimental data on the structural and thermodynamic properties of the liquid alkali metals and their alloys, and the model gives a rather accurate account of the compressibility of liquid metal.
Abstract: Linear screening theory yields expressions for the structure of liquid metals and alloys in terms of the structure of a bare ionic plasma on a rigid background, of the dielectric function of the homogeneous electron gas, and of electron-ion pseudopotentials The results of such an electron-ion plasma model are examined against experimental data on the structural and thermodynamic properties of the liquid alkali metals and their alloys The calculations rely on a very accurate theoretical determination of the structure factor of the classical ionic plasma, which embodies its known equation of state and thermodynamic consistency The model gives a rather accurate account ofthe compressibility of the liquid metal The main empirical adjustments that are included at finite wavenumber are a choice of the plasma parameter at freezing and a large momentum cutoff of the electron-ion coupling, as suggested by melting-curve data and by a discussion of dynamic criteria for the solid-liquid transition in the alkali metals The model is then shown to yield very good agreement with experiment for the detailed shape of the structure factor of the liquid metal near freezing, and for its dependence on pressure, temperature and density A discrepancy with experiment is found in the description of long-wavelength concentration fluctuations in alloys and is attributed to electronic charge transfer between the constituents, which is not included in the model An estimation of the spinodal curve for the Li-Na alloy is presented in support of this conjecture
44 citations
Patent•
02 Oct 1981TL;DR: In this paper, a liquid metal field ionization source is used in conjunction with a three element asymmetric lens system to provide an ion gun having greater magnitude beam currents focused on a smaller spot size than has been previously possible for intermediate energy beams.
Abstract: A liquid metal field ionization source is used in conjunction with a three element asymmetric lens system to provide an ion gun having greater magnitude beam currents focused on a smaller spot size than has been previously possible for intermediate energy beams. An ultra-clean emitter surface is achieved by means of an argon sputtering and/or plasma etching process applied to the emitter surface before liquid metal is applied to the emitter surface to ensure uniform and sufficient flow of liquid metal to the apex of the emitter. The three element asymmetric lens system has a very low chromatic aberration coefficient, enabling precise focusing of beams with large energy spreads. For beam accelerating ratios in the range from 0.2 to 6, the ion gun produces very high current densities in beams focused on very small spot areas, despite the relatively large energy spread of beams produced by liquid metal ionization sources. The energy spread of the ion beam is minimized by operating the emitter at a voltage close to the onset voltage and at a temperature close to the melting point of the liquid metal.
37 citations
37 citations
TL;DR: In this paper, a transient instrument with a liquid metal inglass probe to measure the thermal conductivity of high-temperature melts has been developed, where a wire heat source in the conventional hot-wire method was replaced by a mercury thread contained in a glass capillary.
Abstract: A transient instrument with a liquid metal in‐glass probe to measure the thermal conductivity of high‐temperature melts has been developed. A wire heat source in the conventional hot‐wire method was replaced by a mercury thread contained in a glass capillary. This modification has made it possible to apply the transient method to electrically conducting liquids at high temperature. Satisfactory results were obtained for HTS (Heat Transfer Salt) in the temperature range 457–580 K.
30 citations
TL;DR: In this article, a special subgrid scale heat flux model for liquid metal flows is deduced together with a method of calculating the model coefficients, and the numerical results confirm Lawn's theory, giving reasonable heat flux correlation coefficients which depend only weakly on the problem marking parameters.
30 citations
TL;DR: In this article, a liquid metal field emission source of gold ions has been developed, operating with low heater power (<30 W) and without forced cooling, which can also be used to produce sources of a variety of elements, other than gold, including tin, bismuth, and lead.
Abstract: A fully engineered liquid metal field emission source of gold ions has been developed, operating with low heater power (<30 W) and without forced cooling. The design and performance of the source are described in detail. The present design can also be used to produce sources of a variety of elements, other than gold, including tin, bismuth, and lead. It provides a versatile and reliable research tool which is fully compatible with ultrahigh vacuum installations. Potential fields of application include materials development and surface analysis.
21 citations
TL;DR: In this paper, an fcc solid-solution alloy, Ni-4 W, was used to study the early stages of grain boundary cavitation during creep deformation, and two liquid metals, lead and thallium, were found to be very strong embrittling agents for this alloy, and perhaps other nickle-base alloys.
13 citations
Journal Article•
13 citations
TL;DR: In this article, it was shown that at the metal melting point the interfacial energies become approximately identical for all metals (γUO 2 -liquid metals ≈ 1.676 ± 0.142 J/m 2 ) with respect to an engineering approach, and the respective contact angles (φ s > 90°) point out no wettability.
Patent•
15 May 1981TL;DR: In this paper, a solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn was attached to the channel of a MHD generator, and the mixture is then separated and recycled.
Abstract: A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a MHD generator. Gas enters the oven and a liquid metal enters the mixer. The gas/liquid metal mixture is heated by the collected solar energy and moves through the MHD generator thereby generating electrical power. The mixture is then separated and recycled.
Patent•
08 Oct 1981
TL;DR: In this paper, a stream of liquid metal in the shape of a U is formed, and one of the branches of the stream is subjected to the action of rotary electromagnetic fields, and cooling of its outer surface while ensuring that the metal contained in the other branch remains liquid.
Abstract: The process provides that a stream of liquid metal in the shape of a U is formed, that one of the branches of the stream is subjected to the action of rotary electromagnetic fields, and to cooling of its outer surface while ensuring that the metal contained in the other branch of the stream remains liquid, that a solidified metal is continuously extracted from the cold branch and that the hot branch is supplied with a corresponding quantity of liquid metal, and that the entire stream is subjected to a vertical oscillating movement. At the level where solidification begins, the metal is subjected to the action of a primary electromagnetic field and a deep meniscus is created at the level of the liquid metal by providing at this point a secondary electromagnetic field. The apparatus consists of the conduit of refractory material, one of the branches comprising a water-cooled mould (10) provided with a primary inductor (20) of a frequency below 15 Hz, above which is situated a secondary inductor (30) of a frequency of 50 Hz. The said branch additionally comprises a set of withdrawal or guiding rollers (3) and a fluid jet spraying system (40).
Patent•
30 Apr 1981
TL;DR: In this article, the authors used an excitation winding with an alternating current, and at least two detector windings which are arranged on both sides of the excitation windings.
Abstract: Method for monitoring the flow relationships of a liquid metal, using a detector which consists of an excitation winding which is supplied with an alternating current, and at least two detector windings which are arranged on both sides of the excitation winding. The detector is situated in the direction of flow of the liquid metal. The peak point of the cross-correlation function of the fluctuation signals in the detector windings is checked. By recording the direction of movement, the polarity and the level of the peak point, it is possible to determine the flow relationships, for example a change in the rate of flow, a change in the steam bubble content, the presence of steam bubbles and the rate of migration of the steam bubbles.
Patent•
11 Jun 1981
TL;DR: In this article, the authors describe a solar heat storage unit with a vessel containing a heat storage medium converting between solid and fluid phases, which can be either a chemical compound of the transfer medium or a liquid metal.
Abstract: The solar heat storage unit has a vessel containing a heat storage medium converting between solid and fluid phases. In operation it contains a liquid heat-transfer medium in direct contact with the storage medium. The storage and transfer media have different specific weights. Heat exchangers (4,5) are mounted in the bottom and/or top parts of the vessel (1). The heat transfer medium (3) in the latter can be the same as that (6) inside the heat exchangers. The storage medium can be a chemical compound of the transfer medium, which can be a liquid metal, e.g. a metal halide.
TL;DR: In this article, the effect of grain size on the ductile-brittle transformation of a liquid-metal medium has been investigated on Armco iron in molten Bi, Pb, and their eutectic.
Abstract: The phenomenon of liquid-metal embrittlement is determined to a significant degree by the structure of the material and the conditions of deformation. It has been experimentally established that with an increase in grain size of pure metals and low-alloy alloys the effect of a liquid-metal medium increases. For alloys a linear relationship has been revealed between the true tensile strength and D -~2 (D is the average grain size). However, the majority of investigations have been made at constant temperature. In studying the change in temperature of the ductile-brittle transformation on samples with different grain sizes [i] a linear relationship of it to log D was obtained. The tests were made on u-brass in mercury, and in th~s case there is a possibility of diffusion penetration of the medium. Therefore, it is of interest to investigate the influence of grain size on the temperature range of embrittlement for systems in which diffusion or corrosion solution is practically absent. Below are given the results of such investigations on Armco iron in molten Bi, Pb, and their eutectic. The greatest~umber of tests was made in Pb--Bi eutectic since as a result of its low melting point tests may be made at lower temperatures. Tension of the 9-mm-diam. cylindrical samples was on a reequipped MP-4G unit at a rate of movement of the clamp of 5%/min. Different grain sizes were obtained b~ appropriate heat treatment of the samples in vacuum: anneal at 1200=C for 5 h for 120 ~m; anneal at II00~ for 2 h for 35 ~m; normalize with subsequent tempering at 500~ for i h for 20 ~m. The samples were covered with a solder of the appropriate low-melting metal in the presence of flux, placed in a vessel with the liquid metal, and tested in a vacuum chamber.
TL;DR: In this paper, the thermal and thermal deformation characteristics of laser mirrors made of metal-fiber structures cooled with liquid alkali metals (eutectic heat carriers of the Na-K composition) were investigated.
Abstract: A theoretical investigation is made of the thermal and thermal-deformation characteristics of laser mirrors made of metal-fiber structures cooled with liquid alkali metals (eutectic heat carriers of the Na–K composition). The estimates obtained confirm the possibility of using liquid-metal heat carriers to cool heat-stressed power optics components so as to ensure minimal thermal distortions of the reflecting surfaces.
TL;DR: In this paper, a tandem-mirror fusion reactor was designed to produce fissile fuel for conventional fission-power reactors, and four technologies distinguished by coolant type are: (1) gas, either helium or steam, (2) water, (3) liquid metal, and (4) molten salt.
Patent•
22 Apr 1981
TL;DR: In this paper, a cylindrical body with the bottom isolated from the vessel, a temperature detecting element inserted in it, and also a switching circuit which detects conduction between the body and the vessel through a conductive liquid was used to display the temperature and liquid level on the same display device.
Abstract: PURPOSE:To display the temperature and liquid level on the same display device, by providing a cylindrical body with the bottom isolated from the vessel, a temperature detecting element inserted in it, also a switching circuit which detects conduction between the cylindrical body and the vessel through a conductive liquid, and also a display device. CONSTITUTION:A stainless steel sheath 27 inserted into the metallic vessel 21 is provided to the regular position, and the liquid surface of a conductive liquid 22 is supposed to be on a level with the liquid level as shown by the two-dot chain line. In this case, since the conductive liquid 22 does not allow to contact with the stainless steel sheath 27, the liquid level detection circuit 33 remains opened, the switching circuit 34 is turned off, and display is not performed to the display device 36. Subsequently, when the liquid is allow to contact with the stainless steel sheath 27 as shown by the full line, the liquid detection circuit 33 is closed, voltage of the supply voltage 32 is lowered by the resistor 31, the switching circuit 34 is turned on, an output of the thermo-electric couple 30 is displayed on the display device 36, and it is shown that the liquid level has become the set point or more at the same time. Accordingly, the number of display device can be decreased to half.
Patent•
16 Apr 1981
TL;DR: In this paper, a method for monitoring flow condition of a liquid metal which employs a detector consisting of an excitation coil applied with an a.c. current and at least two detection coils disposed on both sides of said detector is examined.
Abstract: A method for monitoring flow condition of a liquid metal which employs a detector consisting of an excitation coil applied with an a.c. current and at least two detection coils disposed on both sides of said excitation coil. The detector is disposed in the flowing direction of the liquid metal and a peak point of the cross-correlation function of fluctuation signals occurring in said detection coils is examined. By detecting the moving direction, the polarity and the magnitude of the peak point, the flow condition can be comprehensively ascertained, such as a change in flow velocity, a change in void fraction, the presence of voids and transit velocity of void.
TL;DR: In this article, the tensile and bending tests of SM 50 A and STK 55 steels contacting with molten zinc were examined by a special testing apparatus, and the results showed that the reduction of area in molten zinc was reduced to 0.21 and 0.20 at the same temperature in air, respectively.
Abstract: It is known as “Liquid Metal Embrittlement (LME)” that elongation and reduction of area can be markedly reduced when a solid metal is coated with a certain liquid metal and then immediately deformed in tension. There are several reports on the LME cracking of steel structures by molten zinc occured while hot dip zinc galvanizing.In this study, first of all, LME of SM 50 A and STK 55 steels contacting with molten zinc was examined by both tensile and bending tests using a special testing apparatus. The elongation and the reduction of area in molten zinc were reduced to 0.21 and 0.170.20 at the same temperature in air, respectively. However, the tensile strength was almost the same as that of in the air. LME of welded steel joints was also examined in molten zinc. In the second place, the thermal strain variations of a steel pipe which was dipping into molten zinc were measured by using capsule type high temperature strain gages, and the data obtained were converted into thermal stresses. On the other hand, the temperature distributions of the steel pipe which was dipping into molten zinc were analyzed sequentially by using heat equation, and quasi-static thermal stresses were analyzed sequentially by using “Finite Element Method (FEM)”. The thermal stresses measured by using capsule type high temperature strain gages were similar to the analyzed stresses by FEM. The higher the dipping speed in molten zinc becomes, the smaller the thermal stresses are, which occur in the steel pipe while dipping. Therefore, quick dipping is one of the useful countermeasures to prevent the crack occurence in the steel members which are galvanized.
TL;DR: In this paper, a closed analytic form for the free energy of a liquid metal is given using a simple interpolation formula for the dielectric function of the electron gas and a hard-sphere reference system for the description of the liquid structure.
Abstract: A closed analytic form for the free energy of a liquid metal is given using a simple interpolation formula for the dielectric function of the electron gas and a hard-sphere reference system for the description of the liquid structure. The ion electron interaction is described by an Ashcroft-type empty-core potential. Several empirical relationships are substantiated and numerical calculations are performed. The results of the calculations are in reasonable agreement with the experiments.
TL;DR: In this paper, the authors considered the modifications necessary for electron-ion liquids in terms of the response to hypothetical external fields, both generally and in the adiabatic approximation.
Abstract: The thermodynamic expressions for the long-wavelength limits of the partial structure factors given by Kirkwood and Buff are supplemented by expressions for temperature derivatives of the partial chemical potentials in terms of long-wavelength limits of energy density-number density correlation functions. These expressions must be modified when the particle numbers of each species cannot be varied independently and the author considers the modifications necessary for electron-ion liquids in terms of the response to hypothetical external fields, both generally and in the adiabatic approximation. In this approximation the ion-ion interactions are density dependent because of the influence of the conduction electrons and he relates first-order thermodynamic changes in the electron-ion liquid to those in a reference liquid, whose ion-ion interactions are identical at the original density but are independent of density. He uses his results to discuss the thermal diffusion resulting from the driving forces occasioned by electron-ion collisions as the electrons conduct heat along the temperature gradient, reducing the response to that of the reference liquid to effective driving forces and the temperature gradient. Returning to the equilibrium liquid, he evaluates his expression for the temperature derivative of the chemical potential of a pure fluid with density-independent forces, showing how it must be modified to apply to a liquid metal.
TL;DR: In this paper, a theory of stability for a vertical column of a conducting liquid of negligible surface tension under conditions of passage of a direct current through it was developed, and a universal relationship was derived for the shape of the surface of the liquid column.
Abstract: A theory of stability is developed for a vertical column of a conducting liquid of negligible surface tension under conditions of passage of a direct current through it. A universal relationship is derived for the shape of the surface of the liquid column. It is shown that the area of a section of the liquid column decreases as the position of the section is lowered. A new similarity criterion is proposed, which is defined as the ratio of the hydrostatic pressure to the current-induced electromagnetic pressure. This quantity may be called a dimensionless number of gravitational-electromagnetic hydrostatics. The view is expressed that the detachment of liquid from pore walls and the electromagnetic pressure due to the passage of current intensify the infiltration of a porous medium by liquid metal.
Patent•
27 Mar 1981
TL;DR: In this article, a hermetically closed vessel made of a metal membrane forming a gas filling closed space arranged in liquid sodium 4 and a hanging bell 8a of a constant-pressure volume meter 8 arranged in a thermostatic tank 9 are communicated with each other by means of a stainless steel gas conduit pipe 7 the inner diameter of which is selected to be as small as possible.
Abstract: PURPOSE:To improve the measurement accuracy, and facilitate measurement and maintenance operations by using a gaseous mixture capable of reversibly the carbon activity in a carbon-containing liquid metal. CONSTITUTION:A hermetically closed vessel 2 made of a metal membrane forming a gas filling closed space 3 arranged in liquid sodium 4 and a hanging bell 8a of a constant-pressure volume meter 8 arranged in a thermostatic tank 9 are communicated with each other by means of a stainless steel gas conduit pipe 7 the inner diameter of which is selected to be as small as possible. A vacuum pump 20, and carbon series gaseous mixture bomb 22 are connected to the gas conduit pipe 7. Then, the gas filling closed space 3, gas conduit pipe 7 and hanging bell 8a are filled with a gaseous mixture of a predetermined pressure such as a CO-CO2 gaseous mixture of a pressure slightly lower than the atmospheric pressure. As a result, the filled gaseous mixture reflects the carbon activity in the liquid sodium 4 and varies the volume of carbon thereby to detect and measure the carbon activity without using a gas chromatography.
01 Jan 1981
TL;DR: In this paper, a molybdenum, annular wick heat pipe is presented, and performance limitations due to boiling and capillary limits are presented, as well as a design rationale for the heat pipe.
Abstract: High temperature liquid metal heat pipes designed for space power systems have been analyzed and tested. Three wick designs are discussed and a design rationale for the heat pipe is provided. Test results on a molybdenum, annular wick heat pipe are presented. Performance limitations due to boiling and capillary limits are presented. There is evidence that the vapor flow in the adiabatic section is turbulent and that the transition Reynolds number is 4000.
Patent•
30 Apr 1981
TL;DR: In this article, the authors measure the flow rate of the overflowing liquid metal of a two-phase current and facilitate the adjustment of flow rate in a cooling system of a high-speed furnace by a method wherein the bursting liquid metal is once collected into a liquid reservoir, and gas and a liquid are separated.
Abstract: PURPOSE:To measure the flow rate of the overflowing liquid metal of a two-phase current and facilitate the adjustment of flow rate in a cooling system of a high-speed furnace by a method wherein the overflowing liquid metal is once collected into a liquid reservoir, and gas and a liquid are separated. CONSTITUTION:Sodium in a damp tank 1 is sent into a vessel 5 through a valve 3 and a feed piping 4 by means of a pump 2, and sodium in the vessel 5 is flowed into a liquid reservoir through an overflow piping 7 from a liquid surface 6 of sodium. Sodium flowed into the liquid reservoir 8 is returned into a drain tank 1 through a flow rate regulating valve 9 and a drain piping 10. The variation of a liquid-level of the liquid reservoir 8 is detected by means of a level gauge 11 and computed 12, and a flow rate control valve 9 is controlled so as to keep a liquid surface constant. The flow rate of overflowing sodium can be measured from the opening signals of the flow rate control valve 9.
01 Jan 1981
TL;DR: The two-phase generator, liquid-metal magnetohydrodynamic (LMMHD) energy-conversion concept was initially developed at Argonne National Laboratory to meet the anticipated need for an energyconversion system compatible with liquid metal-cooled heat sources, such as the liquid metal fast breeder reactor (LMFBR) and the controlled thermonuclear reactor (CTR) as discussed by the authors.
Abstract: The two-phase-generator, liquid-metal magnetohydrodynamic (LMMHD) energy-conversion concept was initially developed at Argonne National Laboratory to meet the anticipated need for an energy-conversion system compatible with liquid metal-cooled heat sources, such as the liquid-metal fast breeder reactor (LMFBR) and the controlled thermonuclear reactor (CTR). In particular, the use of two working fluids, a thermodynamic fluid (gas or vapor) and an electrodynamic fluid (liquid metal) to provide the electrical conductivity, gives LMMHD great versatility in coupling to differing heat-source temperatures and meeting material constraints, e.g., heat addition can be to the liquid metal, the gas or vapor, or both. Three LMMHD versions are under investigation.