Lockhart

Boxer S G, Goldstein R A, Lockhart D J, Middendorf T R and Takiff L 1989 Excited states, electron-transfer reactions, and intermediates in bacterial photosynthetic reaction centers J. Rhys. Chem. 93 8280-94... 

B. J. Lockhart, M. D. Hampton, and C. J. Bryan, The Oyygen Sensitivityl Compatahility Ranking of Several Materials by Different Test Methods, ASTM Spec. Tech. Publ. 1040, ASTM, Philadelphia, Pa., 1989, pp. 93-105. 

K. C. Hohmann and F. J. Lockhart, "Optimum Heat Exchanger Network Synthesis," AICHE 82nd National Meeting, Adantic City, N.J., 1976. 

The pressure drop for gas—Hquid flow is deterrnined by the Lockhart-MartineUi method. It is assumed that the AP for two-phase flow is proportional to that of the single phase times a function of the single-phase pressure drop ratio P. 

Fig. 33. Lockhart-MartineUi plot for two-phase pressure drop.

J. Sneden, H. Lockhart, and M. Richmond, Tamper-Resistant Packaging, Michigan State University, East Lansing, 1983. 

H. B. Lockhart, Jr., The Environmental Fate of Silver Discharged to the Environment by the Photographic Industry Eastman Kodak Co., Rochester, N. Y., 1980. 

Rapid approximate predictions of pressure drop for fully developed, incompressible horizontal gas/fiquid flow may be made using the method of Lockhart and MartineUi (Chem. Eng. Prog., 45, 39 8 [1949]). First, the pressure drops that would be expected for each of the two phases as if flowing alone in single-phase flow are calculated. The LocKhart-Martinelli parameter X is defined in terms of the ratio of these pressure drops ... 

Lockhart and Martinelh (ibid.) correlated pressure drop data from pipes 25 mm (1 in) in diameter or less within about 50 percent. In general, the predictions are high for stratified, wavy, ana slug flows and low for annular flow The correlation can be applied to pipe diameters up to about 0.1 m (4 in) with about the same accuracy. 

For fully developed incompressible horizontal gas/hquid flow, a quick estimate for Ri may be obtained from Fig. 6-27, as a function of the Lockhart-MartineUi parameter X defined by Eq. (6-131). Indications are that liquid volume fractious may be overpredicled for liquids more viscous than water (Alves, Chem. Eng. Prog., 50, 449-4.56 [19.54]), and uuderpredicted for pipes larger than 25 mm diameter (Baker, Oil Gas]., 53[12], 185-190, 192-195 [1954]). 

FIG. 6-27 Liqi lid volume fraction in liqiiid/gas flow through horizontal pipes. (From Lockhart and MartineUi, Eng. Prog., 45, 3.9 [1.94.9].)... 

Bergelin, Lockhart, and Brown, Trans. Am. Inst. Chem. Engvs., 39, 173 (1943). 

This can be readily integrated numerically as long as we use the appropriate nonequilibrium equivalent specific volume in the integration. A reasonably simple form for has been suggested by Chisholm (1983), which makes use of estabhshed correlations for the slip velocity K, which depends on the Lockhart-Martinelh parameter X. Integrating Eq. (26-118) gives ... 

Find the Lockhart-Martinelh coefficient as defined by Lockhart and Martinelh (1949) ... 

Lockhart, T. J., "Quality Assurance Handbook for Air Pollution Measurement Systems," Vol. IV, "Meteorological Measurements." U.S. Environmental Protection Agency, Research Triangle Park, NC, 1989. 

For our purposes, a rough estimate for general two-phase situations can be achieved with the Lockhart and Martinelli correlation. Perry s has a writeup on this correlation. To apply the method, each phase s pressure drop is calculated as though it alone was in the line. Then the following parameter is calculated ... 

For fog or spray type flow, Ludwig cites Baker s suggestion of multiplying Lockhart and Martinelli by two. 

Lockhart, R. W., and Martinelli, R. C., Proposed Correlation of Data for Isothermal Two-Phase, Two-Component Plow in Pipes, Chemical Engineering Progress, 45 39 8, 1949. 

Lockhart and Martinelli used pipes of one inch or less in diameter in their test work, achieving an accuracy of about -l-/-50%. Predictions are on the high side for certain two-phase flow regimes and low for others. The same -l-/-50% accuracy will hold up to about four inches in diameter. Other investigators have studied pipes to ten inches in diameter and specific systems however, no better, generalized correlation has been found.The way... 

The two-phase pressure drop is obtained by multiplying either the liquid-phase drop by (t) or the gas-phase pressure drop by. Figure 7-23 gives the Lockhart-Martinelli correlation between X and ([t s... 

A number of azacrown compounds were reported by Lockhart and coworkers in 1973. In a typical case, 2-aminophenol was heated at reflux with an equivalent of tet-raethylene dichloride for 48 h. A mixture of the monoaza-15-crown-5 (5) and the mono-aza-12-crown-4 (4) shown in Eq. (4.4) were obtained. Structural assignments were based on H-NMR, IR and mass spectral data. 

In more recent work, Lockhart and Thompson have formed derivatives of 3 by substituting the secondary nitrogen. Substituents include CO—CH2—CH2—CH2—COOH and CH2CH2CH2 0Et. The latter compound should exhibit quite interesting binding properties for alkali metals, but binding constants for these compounds do not appear to have been determined. 

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