Metals, flow

Hsu [Int. ]. Heat Ma.ss Transfer, 7, 431 (1964)] and Kalish and Dwyer [Int. J. Heat Mass Transfer, 10, 1533 (1967)] discuss heat transfer to hquid metals flowing across banks of tubes. Hsu recommends the equations... 

Fig. 11. Photograph of the four-electrode, vacuum flange and dual, quartz crystal, microbalance assembly, (A) side view, and (B) front view, used for mixed Cr atom. Mo atom matrix depositions with simultaneous monitoring of the individual metal flows. (The resolution of the microbalance is 10 g) (113).

In a nuclear power plant, heat must be transferred from the core to the turbines without any transfer of matter. This is because fission and neutron capture generate lethal radioactive products that cannot be allowed to escape from the core. A heat-transfer fluid such as liquid sodium metal flows around the core, absorbing the heat produced by nuclear fission. This hot fluid then flows through a steam generator, where its heat energy is used to vaporize... 

Heineman, J. B., J. F. Marchaterre, and S. Metha, 1963, Electromagnetic Flowmeters for Void Fraction Measurement in Two-Phase Metal Flow, Rev. Sci. Instrum. 34(4) 319. (3)... 

The metal flow rates and capacity in gas atomization are lower than in water atomization. For example, in batch operations, metal flow rates are normally in the range of 1 to 70 kg/min,... 

Roller atomization is a mechanical atomization process. It was invented in the mid 1970 sJ188] In this process, as schematically depicted in Fig. 2.22, a stream of molten metal is fed into the gap between two counter-rotating rolls and forms a thin liquid sheet that subsequently disintegrates into droplets by the mechanical forces. In the original design, a pair of rollers of 100 mm in diameter are mounted in the same horizontal plane and rotate at speeds up to 1250 radians/s. The roll gap is about 50-100 pm, and the metal flow rate is up to 6 kg/min. 

Process parameters of primary importance include roll speed, differential roll speed, roll gap, metal flow rate, metal stream velocity, and melt superheat. The mass median diameter of particles diminishes exponentially as the roll speed increases. It is possible to obtain a smaller mass median diameter when one of the rolls is kept stationary rather than rotating the two rolls at the same speed. Metal flow rate seems to have a negligible effect on the mass median diameter. However, the mass median diameter increases with increasing metal stream velocity, suggesting that the relative velocity of the metal stream to the periphery of the rolls may be a fundamental variable controlling the mass median diameter. The size distribution is approximately constant for the conditions studied. 

Some quantitative studies1498115011 on droplet size distribution in water atomization of melts showed that the mean droplet size increases with metal flow rate and reduces with water flow rate, water velocity, or water pressure. From detailed experimental studies on the water atomization of steel, Grandzol and Tallmadge15011 observed that water velocity is a fundamental variable influencing the mean droplet size, and further, it is the velocity component normal to the molten metal stream Uw sin , rather than parallel to the metal stream, that governs the mean droplet size. This may be attributed to the hypothesis that water atomization is an impact and shattering process, while gas atomization is predominantly an aerodynamic shear process. 

The mass flux in the spray scales with liquid metal flow rate. Gas pressure tends to narrow the spray whereas melt superheat tends to flatten the spray)3] By changing the process parameters and/or manipulating the configuration and/or motion of the spray, the mass distribution profile can be tailored to the desired shape. For example, a linear atomizer produces a relatively uniform mass distribution in the spray. The mass flux distribution in the spray generated with a linear atomizer has been proposed to follow the elliptical form of the Gaussian distribution)178]... 

Methods of near-field, midfield and ensemble (global) imaging and real-time visualization have been developed for monitoring gas atomization of liquid metals.[327] The primary process sensors and monitors used include high-speed video and infrared imaging systems. The process monitors allowed continuous and detailed observations of the atomization process and enabled measurements of the key parameters necessary for adequate control and optimization of the process. The sensors provided the operators with real-time information on the temperature of nozzle tip, visual characteristics of atomization plume, and gas and metal flow rates. The images can be displayed in real time, offering the potential for more responsive process control. 

Whiskers can be incorporated into the metallic matrix using a number of compositeprocessing techniques. Melt infiltration is a common technique used for the production of SiC whisker-aluminum matrix MMCs. In one version of the infiltration technique, the whiskers are blended with binders to form a thick slurry, which is poured into a cavity and vacuum-molded to form a pre-impregnation body, or pre-preg, of the desired shape. The cured slurry is then fired at elevated temperature to remove moisture and binders. After firing, the preform consists of a partially bonded collection of interlocked whiskers that have a very open structure that is ideal for molten metal penetration. The whisker preform is heated to promote easy metal flow, or infiltration, which is usually performed at low pressures. The infiltration process can be done in air, but is usually performed in vacuum. 

Whon the workstone, a, is not connected with the sole-plate, bw, the space between (hem is filled up with a cement formed from ground bone-ash and galena, thoroughly mixed and pressed firmly into it. Before the wOTkstone, and set in masonry inclosed in a cast-iron jacket, is the, lead-pot, g, into winch the freed metal flows through the channel, a a, whioh is sunk beneath the surface of tho plate. It is placed close to the furnace, in order to prevent the escape of lead... 

Ad, with the view of bringing the vapors over as much space as possible, that in the course of which they might deposit the quicksilver. Each of those chamber s has an outlet, s, by which the condensed metal flows out into a receiver, m m, whence it is conducted by a conduit, , into the main tenk. They have likewise an aperture at the top, which la closed, as also that at the base, during the period that the furnace is working. The last chamber in the scries is usually furnished with a number of flanges, or inclined boards, which reach in a slanting direction almost to the oppo-eito wall, upon which a stream of water is continually... 

METAL FLOW LINE NON-METAL FLOW LINE WASTE FLOW LINE CUPOLA... 

The isotope dilution results in Table II are on fuel source samples obtained from NBS which were considered homogeneous. The results in Table III are from the sampling points indicated in Figure 4. These summarized results are mostly by the SSMS general scan technique which has an estimated accuracy of better than 50%. The isotope dilution measurements are limited by the emulsion detector to 3-5%. The results are in grams of metal flow per minute. The mass balance for the various elements was computed by the following equations ... 

Table 6.14. Estimates of heavy metal flows to and from the atmosphere. From Kondratyev et al. (2002b).

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