Separated multiphase flow

FLUENT provides the volume of fluid model (VOF) for the description of separated multiphase flows. The VOF model is based on the resolution of the phase interface in a fixed Eulerian mesh. The conservation equations here are not solved separately for the individual phases but rather for the entire calculation domain with material properties averaged across the phases. For this purpose, an additional conservation equation is introduced for the volume fraction f in the continuous phase. A cell contains either the dispersed phase only f = 0), the continuous phase only f = 1), or the phase interface (0 < / < 1). In order to avoid blurring... 

Sfglf.r, G. 217. 220. 222, 229 Separated flow model, multiphase flow 187 Separation during flow 47... 

In this case, the conventional experimental design is insufficient to ensure accurate estimates of all three multiphase flow functions [34]. We have considered two different modifications in the experimental design that can provide for improved estimates. These modifications can be incorporated separately, or together, thus representing a total of three different candidate experimental designs. 

Richter, H. J., 1983, Separated Two-Phase Flow Model, Application to Critical Two-Phase Flow, Int. J. Multiphase Flow 9(5) 511-530. (5)... 

One of the important issues with RSPs is the development of efficient column internals. Such internals have to enhance both separation and reaction and maintain a sound balance between them. This is valid for both homogeneously and heterogeneously catalyzed processes, being especially important for CD. An understanding of the complex, multiphase flow on the internals interrelated with the mass transport and chemical reaction constitutes a very important challenge for the future. Some first steps in this respect have been done concerning the performance... 

In multiphase flow metering, it is usually required to distinguish hydrocarbon from water. If the liquid phase is "oil continuous," the water fraction can be determined by dielectric constant measurement at microwave frequencies because the dielectric constant of dry hydrocarbon is on the order of 2 to 4 and that of water is 82. Naturally, density measurement can also distinguish water from oil. The next requirement is to distinguish the flow of liquid from the flow of gas in a system where the two will try to separate and travel at different velocities. Cross-correlation by nuclear techniques can measure the density of the stream twice (a short vertical distance apart) and correlate the fluctuations in density with time to determine velocity. Multiphase flow metering is a new and evolving technology,... 

For multiphase systems a rough distinction can be made between systems with separated flows and those with dispersed flows. This classification is not only important from a physical point of view but also from a computational perspective since for each class different computational approaches are required. For multiphase systems involving multiphase flow both Eulerian, mixed Eulerian-Lagrangian, and two-material free surface methods can be used. An excellent review on models and numerical methods for multiphase flow has been presented by Stewart and Wendroff (1984). A similar review with emphasis on dilute gas-particle flows has been presented by Crowe (1982). 

Bubble Separation Process Descriptions and Definitions Based on the Techniques Used for Bubble Generation Bubble Separation Process Descriptions and Definitions According to the Techniques Used for Solids Separation Bubble Separation Process Descriptions and Definitions According to the Operational Modes Surface Adsorption Bubble Phenomena Multiphase Flow Material Balances... 

The mechanics and applications of multiphase flow has been an area of continuing interest to chemical, environmental, and civil engineers (23,77). The multiphase flow patterns may be classified as bubble flow, plug flow, stratified flow, wave flow, slug flow, annular flow, spray flow, and froth flow. Typical sketches of these various flow patterns are shown in Fig. 3. They are self-explanatory. In the field of absorptive bubble separation processes, only multiphase bubble flow and froth flow are of interest to the process engineer. 

Multiphase flow theory is very well developed because of applications such as interfacial separations, petroleum production, and vadose-zone hydrology yet, it remains a mostly empirical science. This is a consequence of the complex physics of flow and because the parameters describing multiphase flow are highly sensitive to pore structure and interfacial configurations. Though three-phase flow is important in applications such as oil production and contaminant transport in the subsurface, we limit the following discussion to two-phase flow for simplicity. 

Banerjee S, Chan AMC (1980) Separated Flow Models-I Analysis of the Averaged and Local Instantaneous Formulations. Int J Multiphase Flow 6 1-24... 

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