Dispersion parameters correlations

Coefficients in Gaussian Plume Dispersion Parameter Correlations"... 

Spray Correlations. One of the most important aspects of spray characterization is the development of meaningful correlations between spray parameters and atomizer performance. The parameters can be presented as mathematical expressions that involve Hquid properties, physical dimensions of the atomizer, as well as operating and ambient conditions that are likely to affect the nature of the dispersion. Empirical correlations provide useful information for designing and assessing the performance of atomizers. Dimensional analysis has been widely used to determine nondimensional parameters that are useful in describing sprays. The most common variables affecting spray characteristics include a characteristic dimension of atomizer, d Hquid density, Pjj Hquid dynamic viscosity, ]ljj, surface tension. O pressure, AP Hquid velocity, V gas density, p and gas velocity, V. ... 

Method of Moments The first step in the analysis of chromatographic systems is often a characterization of the column response to sm l pulse injections of a solute under trace conditions in the Henry s law limit. For such conditions, the statistical moments of the response peak are used to characterize the chromatographic behavior. Such an approach is generally preferable to other descriptions of peak properties which are specific to Gaussian behavior, since the statisfical moments are directly correlated to eqmlibrium and dispersion parameters. Useful references are Schneider and Smith [AJChP J., 14, 762 (1968)], Suzuki and Smith [Chem. Eng. ScL, 26, 221 (1971)], and Carbonell et al. [Chem. Eng. Sci., 9, 115 (1975) 16, 221 (1978)]. 

There exist a number of correlations for the dispersion parameters a-y and CT as a function of downwind distance x and atmospheric stability. These correlations have been reviewed extensively and repeatedly, and the reader is referred to Gifford (1976), Weber (1976), American Meteorological Society Workshop (1977), Doran et al. (1978), Irwin (1979), and Sedefian and Bennett (1980) for comprehensive summaries of the available formulas. In particular, these references provide one with the relations necessary to select <7y and cr for a specific application. We do not endeavor to survey these relations here. 

The parametrization procedure that we have opted for in the most recent works is as follows (1) Compute the intermolecular dynamic correlation energy for the ground state with a second-order Mpller-Plesset (MP2) expression that only contains the intermolecular part and which uses monomer orbitals. Fit the dispersion parameters to this potential. To aid in the distribution of the parameters, a version of the exchange-hole method by Becke and Johnson is sometimes used [154,155], Becke and Johnson show that the molecular dispersion coefficient can be obtained fairly well by a relation that involves the static polarizability and the exchange-hole dipole moment ... 

From this type of analysis, Leonard and Foster conclude that a change in the mean intrinsic residue coefficient best accounts for the lack of correlation between the monochromatic rotations and the dispersive parameters, and they tentatively ascribe this change to alterations in tertiary structure which might affect vicinal interactions, side-chain hydrogen bonds, and so... 

T2 transvers relaxation time) The value Tz/Tj- = 5 has been assumed, where T(- is the correlation time (reciprocal spectral width) of light sources. The coherence parameter P represents the extent of random phase distribution, and the dispersion parameter W represents the degree of regular phase-modulation due to material dispersion (see text for definition). The cross relaxation effect has been neglected. 

To interpret any correlation which may exist between the particular physicochemical texture of certain interfaces and the dispersion factor, a, various authors have introduced a non-dimensional parameter, df, which is prepresentative of the difference from the ideal situation of a perfectly smooth and homogeneous surface. For an interface presenting internal similarity df should be identified to its fractal dimension. Several largely debated relationships have been proposed to determine df from the angle of rotation, 6, or from the dispersion parameter, a, of the capacitive arc. In the present case, we evaluated the complex texture of this type of material by the value of df obtained by the relationship proposed by Le Mehaute et al. (8) for sin red powder electrodes (eg. sintered nickel) df = 1+1/a. 

We used the concept of sound velocity dispersion for explanation of the shift of pulse energy spectrum maximum, transmitted through the medium, and correlation of the shift value with function of medium heterogeneity. This approach gives the possibility of mathematical simulation of the influence of both medium parameters and ultrasonic field parameters on the nature of acoustic waves propagation in a given medium. 

Spray characteristics are those fluid dynamic parameters that can be observed or measured during Hquid breakup and dispersal. They are used to identify and quantify the features of sprays for the purpose of evaluating atomizer and system performance, for estabHshing practical correlations, and for verifying computer model predictions. Spray characteristics provide information that is of value in understanding the fundamental physical laws that govern Hquid atomization. 

---