Metals, liquid correlation

Anta J A, Jesson B J and Madden P A 1998 Ion-electron correlations In liquid metals from orbital-free ab initio molecular dynamics Phys. Rev. B 58 6124-32... 

Special correlations have also been developed for liquid metals, used in recent years in the nuclear industry with the aim of reducing the volume of fluid in the heat transfer circuits. Such fluids have high thermal conductivities, though in terms of heat capacity per unit volume, liquid sodium, for example, which finds relatively widespread application, has a value of Cpp of only 1275 k.l/ni1 K. 

Barnea D, Luniski Y, Taitel Y (1983) Flow pattern in horizontal and vertical two phase flow in small diameter pipes. Can J Chem Eng 61 617-620 Baroczy CJ (1963) Correlation of liquid fraction in two-phase flow with application to liquid metals, NAA-SR-8171. Butterworth, London... 

Correlations for Liquid Metal and Other Fluid Systems... 

For liquid metal boiling, however, Eq. (2-67) showed poor agreement with the experimental results of Bobrovich et al. (1967). In Ivey s correlations, it is expected that the thermodynamic region will not normally be applicable to liquid metals, because their bubble growth is very rarely thermally controlled. Consequently, in this case, Eq. (2-64) for the hydrodynamic region is applicable and is combined with Eq. (2-62), leaving the ratio [tj(tw + td) as a variable ... 

Based on what has been discussed so far, it is recommended that one use an empirical correlation for pool boiling of liquid metals based on data of experimental conditions that match or closely simulate the conditions in question. 

Predictions of the effect of pressure The boiling pressures for liquid metals are relatively low and their critical pressures are high, thus the CHF data are usually obtained in the reduced pressure range of 10-4 to 10 2 and are generally correlated by a simple power function of the form (Dwyer, 1976)... 

The results show a tendency for b to decrease with an increase in pressure, and the higher the critical pressure of a given liquid metal, the less this tendency will be. Thus, in the case of mercury, some correlations show no decrease or a very slight decrease in b over the pressure range compared. However, this theoretical dependence is about three times greater than that observed experimentally with liquid metals, which suggests strongly that these theoretical correlations for CHF require revisions to achieve applicability to liquid metals. 

Summary of experimental data Film boiling correlations have been quite successfully developed with ordinary liquids. Since the thermal properties of metal vapors are not markedly different from those of ordinary liquids, it can be expected that the accepted correlations are applicable to liquid metals with a possible change of proportionality constants. In addition, film boiling data for liquid metals generally show considerably higher heat transfer coefficients than is predicted by the available theoretical correlations for hc. Radiant heat contribution obviously contributes to some of the difference (Fig. 2.40). There is a third mode of heat transfer that does not exist with ordinary liquids, namely, heat transport by the combined process of chemical dimerization and mass diffusion (Eq. 2-162). 

It is noted that additional scales for the property index are shown in Figure 3.42 to correspond to liquid metals as well as water and Freon-22 at different temperatures, indicating the applicability of the correlation to other fluids. 

For very long, helically coiled steam generator tubes, and for conditions typical of liquid-metal fast breeder reactors (LMFBRs), where steam is generated on the tube side, an overall heat transfer correlation for the whole boiling length (from X = 0 to X = 1.0) has been deduced experimentally (Campolunghi et al., 1977b) ... 

Chen, J. C., 1963b, A Proposed Mechanism and Method of Correlation for Convective Boiling Heat Transfer with Liquid Metals, BNL-7319, Brookhaven Natl. Lab., Brookhaven, NY. (4)... 

Koestel, A., M. Gutstein, and R. T. Wainwright, 1963, Fog-Flow Mercury Condensing Pressure Drop Correlation, Proc. 3rd Annual High Temperature Liquid Metal Heat Transfer Tech. Meeting, ORNL-3605, Vol. 2, 198, ORNL, Oak Ridge, TN. (3)... 

As described above, a number of empirical and analytical correlations for droplet sizes have been established for normal liquids. These correlations are applicable mainly to atomizer designs, and operation conditions under which they were derived, and hold for fairly narrow variations of geometry and process parameters. In contrast, correlations for droplet sizes of liquid metals/alloys available in published literature 318]f323ff328]- 3311 [485]-[487] are relatively limited, and most of these correlations fail to provide quantitative information on mechanisms of droplet formation. Many of the empirical correlations for metal droplet sizes have been derived from off-line measurements of solidified particles (powders), mainly sieve analysis. In addition, the validity of the published correlations needs to be examined for a wide range of process conditions in different applications. Reviews of mathematical models and correlations for... 

Table 4.15. Empirical Correlations for Droplet Sizes of Liquid Metals in Gas Atomization Jet Breakup...

Some other correlations that have been specifically developed for liquid metals include those proposed by Nichiporenko)488 Schmitt)489 Thompson)491 and Date et al)494] Nichiporenkol488 correlated the diameter of particles (powder) of predominant fraction, D h with the arithmetic mean particle diameter (linear average diameter), Z)10, and the Reynolds number as well as the Weber... 

Table 4.19. Correlations for Mean Droplet Sizes of Liquid Metals in Centrifugal Atomization...

This approximate relationship is similar to those for centrifugal atomization of normal liquids in both Direct Droplet and Ligament regimes. However, it is uncertain how accurately the model for K developed for normal liquid atomization could be applied to the estimation of droplet sizes of liquid metals Tombergl486 derived a semi-empirical correlation for rotating disk atomization or REP of liquid metals with the proportionality between the mean droplet size, rotational speed, and electrode or disk diameter similar to the above equation. Tornberg also presented the values of the constants in the correlation for some given operation conditions and material properties. 

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