Simulation fluid dynamics

Diffusion in flowing fluids can be orders of magnitude faster than in nonfiowing fluids. This is generally estimated from continuum fluid dynamics simulations. 

FIG. 6-56 Computational fluid dynamic simulation of flow over a square cylinder, showing one vortex shedding period. (From Choudliuty, et al., Trans. ASME Fluids Div, TN-076[1994].)... 

Logtenberg, S. A., Nijemeisland, M., and Dixon, A. G., Computational fluid dynamics simulations of fluid flow and heat transfer at the wall-particle contact points in a fixed-bed reactor, Chem. Eng. Sci. 54, 2433-2439 (1999). 

In this chapter, a number of transport phenomena with entirely different natures are compared for liquids filling porous systems. Here transport can refer to flow, diffusion, electric current or heat transport. Corresponding NMR measuring techniques will be described. Applications to porous model objects will be juxtaposed to computational fluid dynamics simulations. 

Computational fluid dynamic simulator ht-MAH CFD simulation OT indoor airflow and pollutant dispersion Trained %... 

P 28] A 3-D solid model of the cross-shaped micro mixer is meshed to a sufficiently fine scale with brick elements of 2 pm for the simulations [71]. Simulation results were intended at very short time scales, e.g. in intervals of 50 ps, to verify the mixing patterns at the initial state after application of pressure. The numerical values of the mass fraction are taken to give quantitative measures of the mixing efficiency. The pre-processor fluidics solver and post-processor of ConventorWare were used for the simulations. The software FLUENT 5 was used for verification of these results, since the former software is so far not a widely established tool for fluid dynamic simulation. 

Software tools are applied in every step of process development. Tools for individual reactor simulations such as computational fluid dynamic simulations are not the topic in this chapter. These tools supply only numerical data for specific defined reactor geometry and defined specific process conditions. A change of parameter would demand a complete recalculation, which is often a very time-consuming process and not applicable to a parameter screening. Methods for reactor optimization by CFD are described in detail in the first volume of this series. Tools for process simulation allow the early selection of feasible process routes from a large... 

Computational Fluid Dynamics Simulation and Redesign of a Screw Conveyor Reactor... 

Dembele, S., Zhang, J., and Wen, J.X. Assessments of spectral narrow band and weighted-sum-of-gray-gases models for computational fluid dynamics simulations of pool fires. Numerical Heat Transfer Part B, 2005.48(3), 257-276. 

A. K. Das. Computational fluid dynamics simulation of gas-solid risers reactive flow modelling. Phd thesis, Universiteit Gent, 2002. 

Hjertager, B. H., and Morud, K., Computational fluid dynamics simulation of bioreactors. In Bioreactor Performance (U. Mortensen and H. J. Noorman, eds.). Ideon, Lund, 1993, p. 47. 

Computational fluid dynamics simulations were used by Li et al. [68] to determine mass transfer coefficients and power consumption in channels filled with non woven net spacers. The geometric parameters of a non woven spacer were found to have a great influence on the performance of a spacer in terms of mass transfer enhancement and power consumption. The results from the CFD simulations indicated that an optimal spacer geometry exists. 

Computational Fluid Dynamics Simulation of Polymer Flow for Die Design... 

Subramaniam RP, Richardson RB, Morgan KT, et al. 1998. Computational fluid dynamics simulations of inspiratory airflow in the human nose and nasopharynx. Inhal Toxicol 10 473-502. 

Mixing properties and flow fields in stirred tanks are usually studied on a laboratory scale. Practical scale-up of a stirred tank cannot be performed requiring that every individual mixing and fluid mechanical parameters in the small scale tank should be maintained in the larger one. Therefore, scale-up procedures for different types of processes have been determined through experience, testing and computational fluid dynamics simulations. 

The effect of micromixing in the iodination reaction is smaller than that observed for the Friedel-Crafts alkylation using N-acyliminium ions. The smaller effect seems to be ascribed to the smaller rate of iodination, because computational fluid dynamics simulation indicated that the effect of the micromixing on the product selectivity of a competitive consecutive reaction increases with an increase in the reaction rate. Therefore, the electrochemically generated I seems to be less reactive than the N-acyliminium ions. 

Bertola, R, Baldi, G., MARcmsio, D. L. Vanni, M. 2004 Momentum transfer in a swarm of bubbles estimates from fluid-dynamic simulations. Chemical Engineering Science 59, 5209-5215. 

That is, for the molecular dynamics simulations that include energy release chemistry steps to be realistic, these chemical steps must have two features. They must have an endothermic component such that initial chemical events remove rather than release energy, and they must have exothermic steps that release a fraction rather that all the chemical energy into product translation. That fraction must come from calculations such as those discussed in this chapter. These two features are the MD-simulation equivalent of chemical induction times in fluid dynamics simulations. 

Bottom row results from FEMLAB computational fluid dynamic simulation of process. 

COMPUTATIONAL FLUID DYNAMICS SIMULATIONS OF SUPERSONIC JET-NOISE REDUCTION CONCEPTS... 

STATISTICAL AND FLUID DYNAMIC SIMULATIONS, AND ALSO COMPUTERS HARDWARE DEVELOPMENT IN THE HUDSON VALLEY... 

Figure 4.1-4. Computational fluid dynamics simulation of vapor fraction formation from a tube contraction as a function of tube length (diameter = 500pm, pressure drop = 3.45 MPa). Red areas indicate 100% vapor regions within the pipe. (This figure is available in full color at ftp //ftp.wiley.com/public/sci tech med/pharmaceutical biotech/.)...

Trivex Pin. Two-dimensional (2-D) computational fluid dynamics simulations were used to examine material flow around a series of pin... 

In this section, some other relevant aspects of the rheology of polymer melts are addressed in some detail. The case of filled systems is discussed first. These types of systems are of significant importance in industrial applications. In addition, molecular dynamic and fluid dynamic simulations that have greatly benefited from the significant advances in computer power are discussed to some extent. 

Computational fluid dynamic simulations have been nsed to model the drop/partiele trajectories in spray-drying (Gianfrancesco et al., 2010), but optimization is still complex. 

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