Multiphase fluids

Occasionally, piping systems are designed to carry multiphase fluids (combinations of gases, Hquids, and soflds), or non-Newtonian fluids. Sizing piping for such systems is beyond the scope of this article. PubHcations covering multiphase flow (20) and non-Newtonian flow (21) are available. 

Fig. 4. Multiphase fluid and fluid—solids reactors (a) bubble column, (b) spray column, (c) slurry reactor and auxiUaries, (d) fluidization unit, (e) gas—bquid—sobd fluidized reactor, (f) rotary kiln, and (g) traveling grate or belt drier.

The multiphase fluid systems of interest are often opaque, and thus noninvasive techniques based on optical methods or using laser beams are not effective. Various experimental techniques are available and continue to be developed to characterize opaque multiphase flows. 

Y. Inoue, Y. Chen, and H. Ohashi, A mesoscopic simulation model for immiscible multiphase fluids, J. Comput. Phys. 201, 191 (2004). 

Zhang K., Moridis G., et al. TOUGH+C02 A multiphase fluid-flow simulator for C02 geologic sequestration in saline aquifers. 2011 Computers Geosdnces 37 714— 723. 

Pruess K. TOUGH2 A genaral simulator for multiphase fluid and heat flow. 1991 Lawrence Berkeley National Laboratory Report, LBNL, California 29400. 

Quite new ideas for the reactor design of aqueous multiphase fluid/fluid reactions have been reported by researchers from Oxeno. In packed tubular reactors and under unconventional reaction conditions they observed very high space-time yields which increased the rate compared with conventional operation by a factor of 10 due to a combination of mass transfer area and kinetics [29]. Thus the old question of aqueous-biphase hydroformylation "Where does the reaction takes place " - i.e., at the interphase or the bulk of the liquid phase [23,56h] - is again questionable, at least under the conditions (packed tubular reactors, other hydrodynamic conditions, in mini plants, and in the unusual,and costly presence of ethylene glycol) and not in harsh industrial operation. The considerable reduction of the laminar boundary layer in highly loaded packed tubular reactors increases the mass transfer coefficients, thus Oxeno claim the successful hydroformylation of 1-octene [25a,26,29c,49a,49e,58d,58f], The search for a new reactor design may also include operation in microreactors [59]. 

Reactive absorption, reactive distillation, and reactive extraction occur in multicomponent multiphase fluid systems, and thus a single modeling framework for these processes is desirable. In this respect, different possible ways to build such a framework are discussed, and it is advocated that the rate-based approach provides the most rigorous and appropriate way. By this approach, direct consideration... 

Soo, S. L. (1990). Multiphase Fluid Dynamics. Beijing Science Press Brookfield USA Gower Technical. 

Clearly, the capability of relatively rapid and inexpensive numerical solutions of a proposed set of governing equations or boundary conditions that can be used in an interactive way with experimental observation represents a profound new opportunity that should greatly facilitate the development of a theoretical basis for fluid mechanics and transport phenomena for complex or multiphase fluids that are the particular concern of chemical engineers. 

Fraser Russell I d like to say a bit about multiphase fluid mechanics. If one is concerned with design and, as Gary said, focusing on the macroscale (Fig. 1), one needs a lot more information about the creation and/or movement... 

PORFLOW A software tool for multiphase fluid flow, heat and mass transport in fractured porous media. User s manual. Version 3.07. -Analytic Computational Research, Inc. (ACRi). 

Harlow, F. H., and Amsden, A. A., Numerical calculation of multiphase fluid flow. J. Comp. Phys. 17, 19 (1975). 

Noble gases exist in formation waters as uncharged, nonpolar species. They preferentially partition from aqueous solutions into nonpolar solvents such as crude oil and natural gas (Kharaka and Specht, 1988). The degree of partitioning depends on such factors as temperature, gas atomic radius, and the salinity of the aqueous phase. Distinct variations in Ne/ Ar, Kr/ Ar, and °Xe/ Ar are produced by fractionation in multiphase fluid systems. These variations have been used as a tool in oil exploration and reservoir evaluation. Pinti and Marty (2000) give detailed examples of these applications in the Pannonian Basin, Hungary and in the Paris Basin, France. 

Hewitt GF, Multiphase fluid flow and pressure drop Introduction and fundamentals, in Hewitt GF (Ed.), Hemisphere Handbook of Heat Exchanger Design, Hemisphere Publishing Corporation, New York, 2.3.1-1-2.3.1-10, 1990. 

The above-described mixers are essentially low-viscosity devices. In many operations where the viscosity is high, when dealing with concentrated multiphase gas-liquid-solid binary or tertiary systems, or when liquid-to-solid phase transformation occurs during mixing, novel equipment designs are needed to intensify the heat/mass transfer processes. The multiphase fluids also represent an important class of materials that have microstructure developed during processing and subsequently frozen-in, ready for use as a product. To deliver certain desired functions, the control of microstructure in the product is important. This microstructure is developed in most cases by the interaction between the fluid flow and the fluid microstructure hence, uniformity of the flow field is important. 

The pore-size distribution of porous media is inherently important, as it is directly related to such characteristics as fluid flow and storage, and multiphase fluid distribution and displacement. The methods used to measure the pore-size distribution include image... 

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