Measurement computation fluid dynamics

In theory it should be possible to calculate the capture efficiency without measurements. Some attempts have used computational fluid dynamics (CFD) models, but difficulty modeling air movement and source characteristics have shown that it will be a long time before it will be possible to calculate the capture efficiency in advance. ... 

There are many nonintrusive experimental tools available that can help scientists to develop a good picture of fluid dynamics and transport in chemical reactors. Laser Doppler velocimetry (LDV), particle image velocimetry (PIV) and sonar Doppler for velocity measurement, planar laser induced fluorescence (PLIF) for mixing studies, and high-speed cameras and tomography are very useful for multiphase studies. These experimental methods combined with computational fluid dynamics (CFDs) provide very good tools to understand what is happening in chemical reactors. 

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. 

There have been several studies in which the flow patterns within the body of the cyclone separator have been modelled using a Computational Fluid Dynamics (CFD) technique. A recent example is that of Slack et a/. 54 in which the computed three-dimensional flow fields have been plotted and compared with the results of experimental studies in which a backscatter laser Doppler anemometry system was used to measure flowfields. Agreement between the computed and experimental results was very good. When using very fine grid meshes, the existence of time-dependent vortices was identified. These had the potentiality of adversely affecting the separation efficiency, as well as leading to increased erosion at the walls. 

In order to obtain a reliable scale-up rule one would have to perform measurements in larger vessels (D > 1 m) [52]. Unfortunately, in this case, this otherwise outstanding and comprehensive decolorization method fails completely thick water layers glimmer pale blue and the white painted vessels make the perception of the color change difficult. Consequently, in this field, computational fluid dynamics (CFD) will possibly provide a solution. 

A comparison of the predicted results from a calibrated computational fluid dynamics (CFD) model with experimentally measured hydrogen data was made to verify the calibrated CFD model. The experimental data showed the method predicted the spatial and temporal hydrogen distribution in the garage very well. A comparison was then made of the risks incurred from a leaking hydrogen-fueled vehicle and a leaking liquefied petroleum gas (LPG)-fueled vehicle. 

Over recent years, a great deal of numerical modeling work has been carried out using computational fluid dynamics to derive particle charging models " however, the basic models need experimental support because the equations cannot be analytically solved. A reasonable alternative to modeling is proposed by Cochet, " who developed an equation, which appears to give reasonable correlation to actual precipitator measurements in the critical size range, as tested and reported by Hewitt. 

Grochowicz et al. modeled the secondary flow in serpentine and coiled tubes as the measure of the radial mixing using computational fluid dynamics techniques. They showed that flow characteristics in serpentine tubes result in considerably less band broadening per unit length than in linear tubes of the same inner... 

Strain-Rate Estimates in the Stir Zone. Strain rates during FSW have not been measured experimentally. However, several modeling techniques have been used to estimate the strain rates during FSW of aluminum alloys, including a kinematic approach (Ref 8), CTH or hydrocode (Sandia National Laboratories) (Ref 9), computational fluid dynamics models (Ref... 

Measurements have been made of turbulence structure by a number of workers using laser-Doppler methods and using hot-film anemometry Application of computational fluid dynamics to turbulent flow in stirred tanks is developing rapidly and involves using assumptions inherent in Kolmogoroff s theory and turbulence measurements to supply boundary conditions. 

Papadakis and King (1988a,b) used this PSI-Cell model to simulate a spray dryer and compare their predicted results with limited experimental results associated with a lab-scale spray dryer. They have shown that the measured air temperatures at various levels below the roof of the spray drying chamber were well predicted by the computational fluid dynamics (CFD) model. Negiz et al. (1995) developed a program to simulate a cocurrent spray dryer based on the PSI-Cell model. Straatsma et al. (1999) developed a drying model, named NIZO-DrySim, to simulate aspects of... 

To illustrate application of the more complex systems approach of integrating computational fluid dynamics (CFD) with intracellular kinetics we again take as a first example Sacchararomyces cerevisiae for which a dynamic model for the glycolysis based upon measurements of intracellular metabolites has been presented earlier [64,70]. To reduce the complexity of this model, the simplified version for anaerobic growth will be used. Measured data and model structure have been discussed above [71]. Simulations have been performed for a production... 

To compare the hydrodynamic behavior of supercritical CO2 and water, laser-Doppler velocimetry (LDV) measurements have been performed in a specially designed high-pressure mixing vessel provided with glass windows. For the same geometry. Computational Fluid Dynamics (CFD) calculations have been made for both media. 

This is commonly done by a stroboscopic measurement setup comprising a microscope-mounted CCD camera with a short exposure time and a flashlight which are synchronized to the rotational motion (Fig. 15). Regarding simulation, the majority of commercially available computational fluid dynamic (CFD) packages is able to cope with rotating channels. 

As computational fluid dynamics (CFD) has been commonly employed in the investigation of mine ventilation, the main features of the ventilation, such as flow pattern, air velocity and pressure variation can be obtained through simulations. Although conveyance motion can be measured experimentally with up-to-date techniques, httle attention has been paid to the simulation of the motion of conveyances, especially the comparison of influences from various... 

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