Showing papers on "Liquid metal published in 1972"

Variables affecting the nature of the chill zone

Abstract: Structures and substructures in the chill zone have been studied in Al-Cu alloys as a function of the following solidification conditions at the substrate chill: a) heat sink capacity; b) surface microprofile; c) nature of the liquid metal fluid flow as it makes substrate contact. The parameters taken in account both experimentally and analytically are: heat transfer coefficient of the metal/mold interface, surface rugosity of the mold walls, and the Reynolds number of the liquid metal fluid flow. The results obtained show definite correlations between the structural characteristics of the chill zone and the values of the studied parameters.

Immersion pump for pumping corrosive liquid metals

Abstract: Immersion pump having slight bulk, for liquid metals, operating by conduction, consisting of one or two magnetic circuits, a conduction loop made of liquid metal and of two electrodes limiting the liquid metal duct in the active zone. A refractory material is cast round the components of the pump, and protects them against the corrosive action of the liquid metal. The part which is not immersed comprising the induction windings of the magnetic circuits is protected by a cast aluminum steel housing.

Associative adsorption on liquid iron

Abstract: The depression of the surface tension of a liquid metal by a binary surface compound which is formed from a pair of solutes is considered. The necessary thermodynamic equations are developed for the case in which the solutes are not separately surface active. It is shown that the published experimental results for liquid Fe-Cr-C alloys are fully consistent with the formation of the surface compound “CrC” and that the results for Fe-Si-C alloys might indicate coverage by “SiC”.

A Study on the Measurement of the Local Void Fraction by the Optical Fibre Glass Probe : 1st Report, On the Method for the Measurement of the Local Void Fraction in a Liquid Metal Two-Phase Flow

Abstract: The local void fraction is one of the most essential parameters to clarify the precise structure of a two-phase flow. In the report, a new method is tried for the measurement of the local void fraction. The method is based on the principle that if there is a liquid metal at the top of the optical fibre glass probe, the signal light reflects and turns back the fibre glass. If not, the signal light scatters out. In the first report, the measurement is carried out in the case of a mercury-air two-phase flow in a vertical pipe. The present results show good agreement with those obtained by the method of pressure gradient.

Partial Heats of Mixing in the Bi-Sn system

Abstract: Partial heats of mixing have been measured at 725 K for liquid Bi-Sn alloys using a liquid metal solution calorimeter. Integral heats of mixing were calculated and were found to be endothermic. The experimental data are analyzed using the subregular model and the modified quasichemical model.

Liquid metal transport properties

Abstract: Viscosity and self-diffusivity data for ten liquid metals are correlated by use of the theory of corresponding states and the reducing factors defined by Helfand and Rice. The transport data are used to determine relative values of the pair-potential energy parameters, which are found to have a linear relationship with melting point. By using density data, it is possible to construct reduced correlations for diffusivity and viscosity as functions of reduced temperature without explicitly choosing distance parameters

The thermal conductivities of liquid lead and indium

Abstract: Thermal conductivity measurements have been made on lead over the range 620-880K and on indium over the range 520-845K using a new apparatus of the axial flow type. In each case, the Lorentz number for the liquid metal falls steadily with increasing temperature.

Level gauge of liquid metal

Abstract: A level gauge of liquid metal which has a detecting element formed with a primary coil and a secondary coil, a compensating element formed with a primary coil and a secondary coil, both elements being inserted in a container of liquid metal, said compensating element covered with metal so as to have a magnetic permeability equal to that of the liquid metal. The output of an oscillator is supplied to the primary coils of the detecting element and compensating element to detect the difference of the induced output at the secondary coils of the respective elements. Thus, reliable measurement may be obtained thereby.

Process and apparatus for supplementary cooling of the center of a continuously cast metal bar

Abstract: An improved process and device for the continuous casting of metal bars wherein an inert gas is insufflated into the liquid metal in the mould through a metal pipe dipped into said liquid metal and having substantially the same composition of the said liquid metal.

Contact reaction of refractory compounds with liquid metals

Abstract: 1. A study was made of the reaction of liquid iron-group metals with carbids of Subgroup-IVa metals. It was established that reaction does take place in these systems, resulting in the formation of limited solid solutions and eutectic alloys. 2. The distribution of wetting metals in the carbides was investigated by the technique of electron-probe microanalysis. It was found that the averaged distribution of the iron-group metals over the depth of carbide specimens is closely approximated by a hyperbolic function. The nature and concentration of the wetting metal and the reaction temperature are the key factors controlling the distribution of wetting metals in the contact zone.

Liquid metal steam generator

Abstract: A liquid metal heated steam generator which in the event of a tube failure quickly exhaust out of the steam generator the products of the reaction between the water and the liquid metal. The steam is generated in a plurality of bayonet tubes which are heated by liquid metal flowing over them between an inner cylinder and an outer cylinder, the inner cylinder extending above the level of liquid metal but below the main tube sheet, and a central pipe extends down into the inner cylinder with a centrifugal separator between it and the inner cylinder at its lower end and an involute deflector plate above the separator so that the products of a reaction between the liquid metal and the water will be deflected downwardly by the deflector plate and through the separator so that the liquid metal will flow outwardly and away from the central pipe through which the steam and gaseous reaction products are exhausted.

The role of dissolved oxygen in the corrosion of niobium and tantalum by liquid sodium

Abstract: The corrosion of niobium and tantalum in liquid sodium is strongly influenced by the quantity of dissolved oxygen in the liquid metal. The oxides Na3TaO4 and Na3NbO4 have been identified on the surface of tantalum and niobium after immersion in liquid sodium containing dissolved oxygen at temperatures in excess of 300°. The oxides were identified by their X-ray powder diffraction patterns which were recorded through a matrix of sodium. Measurement of the lattice constant of the underlying transition element enabled the extent of oxygen solid solution to be calculated. The formation of an oxide, together with oxygen in solid solution, enables a mechanism of corrosion for niobium and tantalum in the presence of liquid sodium to be established.

The stability of negative ions in liquid metals

Abstract: The model potential of Hunt and Moiseiwitsch (1970) for the calculation of electron affinity is modified to simulate the potential of a negative ion in a liquid metal. It is found that, as a result of screening by conduction electrons, halide ions bind an additional electron more tightly in a liquid alkali metal than in free space. The method is extended to O-- ions. The theory predicts that O-- ions are electronically stable in liquid sodium, but results for liquid caesium are less conclusive.

Fail-safe liquid pumping and flow control system

Abstract: A fail-safe liquid metal pumping and flow control system is described wherein metal is transferred from a holding furnace to a continuous casting mold, individual molds, ladles, etc., through a siphon having an electromagnetic pump with dual direction output situated along the length of the siphon to control the flow of liquid metal therethrough. The system initially is primed by applying vacuum to the siphon through a suitable valve and the siphon is vented to terminate liquid metal flow upon sensing of an anormal process condition, e.g., loss of electrical power to the electromagnetic pump, to inhibit further siphoning of liquid metal from the reservoir. Also disclosed is a pumping system wherein the holding furnace is initially disposed at an attitude to inherently raise the liquid metal level into operating engagement with an electromagnetic pump drawing liquid metal from the holding furnace. The furnace then is tilted upon the subsequent sensing of an anormal process condition to gravitationally return metal from the electromagnetic pump to the holding furnace. The electromagnetic pump thus provides the lifting force to drive the molten metal up to and over the pouring spout, thereby providing complete electrical control of the pouring rate, while failure of power or the pump will cause the flow to terminate to provide the fail-safe feature.

High frequency induction plasma burner - with integral cooling

Abstract: External spiral grooves in the ceramic combustion chamber house a double wound high frequency induction coil which also carries the cooling fluid. The coil is metal bonded to the ceramic chamber to promote good thermal contact. Alternatively, a single spiral coil can be used when liquid metal is used as both conductor and coolant. The coil may be embedded in the ceramic as an alternative to grooves and metal bonding.

Sorption agent for nonsolid metals

Abstract: 1. A METHOD OF COLLECTING A LIQUID METAL SELECTED FROM THE GOUP CONSISTING OF MERCYRY, GALLIUM, ROSE''S METAL, AND WOOD''S METAL WHICH COMPRISES CONTACTING SAID LIQUID METAL WITH A SOLID, ABSORBENT CARRIER IMPREGNATED WITH A WATER-SOLUBLE SALT OF A METAL MORE NOBLE THAN SAID LIQUID METAL UNTIL SAID LIQUID METAL REACTS WITH SAID SALT OF THE MORE NOBLE METAL TO FORM A SALT OF SAID LIQUID METAL, AND THE FORMED SALT IS ABSORBED BY SAID CARRIER.

Liquid metal conduction pump

Abstract: A conduction pump having a simple structure for liquid metal, comprising a coil constituted by a refractory casing containing liquid metal and a metal flow duct connnected to the casing by two end pieces each comprising at least one opening.

Method of producing multi-layer metal ingots

Abstract: A method of producing multi-layer metal ingots providing a portion-by-portion filling of metal into the casting mould through liquid slag and crystallization of each portion of metal formed under the liquid slag, the temperature of which is maintained higher than the metal melting temperature of the layer being crystallized under it, each subsequent portion of metal being poured onto the preceding crystallized layer until an interlayer of liquid metal constituting 0.02 to 0.2 of its thickness is maintained over it.

Field-ion-microscope studies of the interface between solid-liquid metals in vacuum

Abstract: An exploratory field‐ion‐microscope study of the interface between solid and liquid metals in vacuum is reported using a Ga–In–Sn alloy as the liquid metal. The result with tungsten was no surface atom rearrangement at the interface; with molybdenum, the formation of an alloy of unidentified crystal structure; with iridium, no alloy formation but dissolution of a part of the tip; and with platinum, complete dissolution of the tip.

Simplified thermochemistry of oxygen in lithium and sodium for liquid metal cooling systems

Abstract: Plots of oxygen chemical potential against composition of lithium-oxygen solutions and sodium-oxygen solutions for a range of temperature were constructed. For each liquid metal two such plots were prepared. For one plot ideal solution behavior was assumed. For the other plot, existing solubility limit data for oxygen in the liquid metal were used to determine a first-order term for departure from ideality. The use of the plots in evaluating the oxygen gettering capability of refractory metals in liquid metal cooling systems is illustrated by a simple example involving lithium, oxygen, and hafnium.

Composite Temperature-Pressure Measurement Instrument for Advanced Reactors

Abstract: Operating theory and characteristics given in this paper concern a dual property measurement sensor and associated instrumentation for use with liquid metal cooled, fast breeder nuclear reactors. The sensor may also be applied in other similar severe environments. Pressure variations are sensed by deflection of a thin diaphragm which forms one end wall of a resonant cylindrical microwave cavity. Temperature changes cause the cavity size, and thus its resonant frequency to vary. Both physical properties may be continuously monitored as each relates to a distinct mode of cavity resonance. Precise digital readout of the resonant frequencies indicated a sensor sensitivity to pressure of about 9 MHz/psi (for null pressure scheme of operation), and to temperature of 350 kHz/°F. As both the sensor and connecting waveguide are entirely of metal, direct immersion in a liquid metal coolant should be possible.

On the question of conductivity nature of metals in the supercritical state

Abstract: During recent years some works on the measurements of conductivity and state equation of cesium and mercury in the supercritical state have been published. This made it possible to find the dependence of conductivity upon the density for cesium and mercury. However, it was difficult to understand the nature of conductivity because one had no information on microstructure of substance in the supercritical state. This work is made as an attempt to understand the structure variation of metal in the supercritical state on the basis of model experiments with solid metallic spheres and with the help of these data to explain the dependence of conductivity upon the density of metal. Than one can divide the whole diapason of densities of the metal from liquid state to solid state into three regions: (1) the region of the common liquid metal, (2) the region of the liquid metal, where separate atoms of the metal due to thermal mobility can displace themselves on the distances where the kinetic energy of an electron become less than the energy of Coulomb interaction and the electron leave the zone of conductivity, (3) the region where the metallic conductivity is absent completely at any temperature. The continuing of the curve of liquid gas equilibrium may be used as the conventional boundary of the region where because of statistical distribution there are about 50% similar liquid density and 50% similar gas density. The gas part of the density is increased with increasing temperature, whereas decreasing of the temperature leads to increasing of the liquid part of the density. Comparing the experimental curves on the line of coexistence for different substances, one can conclude that cesium has the greatest compressibility having at the same time the highest conductivity.

Interaction of liquid gallium with copper

Abstract: The mechanism of the interaction of liquid gallium with copper powder at 100°C was studied. Data on the characteristics of the growth of the Θ -phase (the compound CuGa2) were used to develop a method of calculating the effective thickness of intermetallic compound layers formed as a result of the interaction between liquid metals and metal powders and an appropriate formula was derived. It was established that the growth of the Θ-phase formed as a result of the interaction in liquid gallium and copper at 100°C follows a parabolic law.

Incipient Boiling Pressure Pulse of Sodium under Forced Convection by Direct Heating

Abstract: An account is given of experiments on incipient boiling pressure pulses imparted by liquid sodium, performed in a forced convection loop. The sodium is heated by direct current applied to the liquid metal itself in a vertical tube of 14.9 mm inner diameter through which the medium pumped. The experiments were carried out with the following ranges: Input power: 6–12kW,Pressure at condenser: 0.6–1.0 kg/cm2, Inlet temperature: 780°–850°C, Flow rate: 1.0–3. 5 l/min Typical pressure pulses registered during incipient boiling presented the form of damped oscillation. The initial pressure pulses were dependent on the location of boiling inception along the test section, the incipient boiling pattern and the degree of superheat. The initial pressure pulses observed were in the range of 0–3. 5 kg/cm2. The pressure pulses increased with the degree of superheat, which ranged 0°–150°C. The magnitudes of pressure pulses exceeded the saturation vapor pressure corresponding to the temperature of superheated liquid. Cons...