Shear induced state , turbulence

Lopez de Bertodano [92] stated that this simple modification has a big effect on the dynamic and the asymptotic behavior of the model. At a later stage, [93] also stated that the bubble induced time constant, which is proportional to the residence time of a bubble, is usually very short compared to the time constant of the shear induced turbulence. They concluded that for most practical cases the transport equation for bubble induced turbulence (5.13) can be reduced to fcei = fceia-... 

The reactor vessel is usually a stirred tank. The monomer phase is subjected either to turbulent pressure fluctuations or to viscous shear forces, which break it into small droplets that assume a spherical shape under the influence of interfacial tension. These droplets undergo constant collisions (collision rate >1 s ), with some of the collisions resulting in coalescence. Eventually, a dynamic equilibrium is established, leading to a stationary mean particle size. Individual drops do not retain their unique identity, but undergo continuous breakup and coalescence instead. In some cases, an appropriate dispersant can be used to induce the formation of a protective Aim on the droplet surface. As a result, pairs of clusters of drops that tend to coalesce are broken up by the action of the stirrer before the critical coalescence period elapses. A stable state is ultimately reached in which individual drops maintain their identities over prolonged periods of time [247]. 

The effects of flow rate (flow intensity, turbulence, shear stress) on corrosion have been known for a long time and have been variously called erosion corrosion or flow induced localized corrosion (FILC), which latter term is preferred because it denotes a purely aqueous (liquid) phenomenon, while erosion generally includes the presence of a solid phase. An attempt was made in 1990 to summarize the state of the art of FILC in a symposium [54]. The following is a brief synopsis of the developments in this area, with emphasis on corrosion inhibitor testing. 

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