Taylor-Couette vortices

Preparation of Monodisperse, Spherical Oxide Particles by Hydrolysis of Metal Alkoxide Using a Couette-Taylor Vortex Flow Reactor... 

As an alternative to a cascade of CSTR trains, a novel continuous reactor with a Couette-Taylor vortex flow (CTVF) has been proposed, which can realize any flow pattern between plug and perfectly mixed flows [361-366]. A continuous Couette-Taylor vortex flow reactor (CCTVFR) consists of two concentric cylinders with the inner cylinder rotating and with the outer cylinder at rest. Figure 29 shows a typical flow pattern caused by the rotation of the inner cylinder. 

Nomura et al. [360,364] first utilized a Couette-Taylor vortex flow reactor (CTVFR) for the continuous emulsion polymerization of St to clarify its char-... 

Couette-Taylor Continuous emulsion pol)mierization of styrene in a Couette-Taylor vortex flow reactor comprehensive kinetic study in dependence on reactor operation parameters 179... 

Reactor configurations involved in continuous emulsion polymerization include stirred tank reactors, tubular reactors, pulsed packed reactors, Couett-Taylor vortex flow reactors, and a variety of combinations of these reactors. Some important operational techniques developed for continuous emulsion polymerization are the prereactor concept, start-up strategy, split feed method, and so on. The fundamental principles behind the continuous emulsion polymerizations carried out in the basic stirred tank reactor and tubular reactor, which serve as the building blocks for the reaction systems of commercial importance, are the major focus of this chapter. 

This is most easily achieved by rotating the inner cylinder and keeping the outer fixed in the laboratory frame. Note, however, that this geometry leads to the formation of Taylor vortex motion if inertial effects become important (Reynolds number Re 1). Most rheo-NMR experiments are actually performed at low Re. In the cylindrical Couette, the natural coordinates are cylindrical polar (q, <(>, z) so the shear stress is denoted and is radially dependent as q 2. The strain rate across the gap is given by [2]... 

The most promising is the application of the Taylor-vortex column with Taylor-Couette flow. Sorption of hydrophobic organic compounds can lead to under estimation of actual removal efficiency of wastewater treatment, as weU as cross-contamination of the batches of the effluent due to release ofthe sorbed solute molecules. This is supported by the results ofthe laboratory studies, along with the ease ofthe potential scale-up. The critical part in the context ofthe removal of organic compounds from wastewater(s) is the material of the inner cylinder. The surface of the inner cylinder provides a potential sorption surface for hydrophobic organic molecules. Since the PTFE price could be prohibitive for the scale-up, stainless steel, or other materials should be explored as replacements for potential industrial applications. 

Dr Coney (1971) researched Taylor vortex flow with particular interest in rotary heat exchangers, which he later used in a rotary vapour compression cycle heat pump. Taylor-Couette flows are used in commercial intensified reactors now (see Chapter 5). 

Couette flow is a laminar circular flow occurring between a rotating (inner) cylinder and a static one, and the extension via increased speed of rotation to centrifugally-driven instabilities leads to laminar Taylor vortex flow, tending to turbulent flow as speed increases. Poiseuille flow is axial. 

Giordano, R.L.C., Giordano, R.C. and Cooney, C.L. (2000). Performance of a continuous Taylor-Couette-Poiseuille vortex flow enzymic reactor with suspended particles. Process Biochemistry, Vol. 35, No. 10, pp. 1093-1101. 

Taylor vortices are toroidal in form and constitute a secondary laminar flow superimposed on the basic Oouette flow. For many years it has been suggested that the sequence of flows occurring as the Taylor number is increased is Couette flow, Taylor vortex flow, wavy Taylor vortex flow with travelling azimuthal waves superimposed on the... 

The critical Taylor number T for the onset of Taylor vortices can be predicted by examining the stability of snail amplitude disturbances when superimposed on the basic Couette flow. The use of this linear stability analysis for concentric cylinders has been extensively reviewed by Chandrasekhar (1) and Stuart (2). All such analyses assune that the cylinders are infinitely long. In addition to T they predict an initial Taylor vortex celf axial length, . ... 

Fig. 4. The computation of the dimension of an attractor is illustrated using velocity data obtained fof a weakly turbulent flow in the Couette-Taylor system at R/R =16.0, where R is the Reynolds number for the onset of time-independent Taylor vortex flow. The different curves correspond to different embedding dimensions m. (a) The dependence of N(e), the average number of points within a ball of radius e, on e. (b) The slope of the curves shown in (a). Regions A,...

The study of laminar vortical structures has been well documented in the Taylor-Couette (TC) flow for an extensive range of gap sizes [33]. Of particular interest are the experimentally determined boundaries in the map of flow regimes [34], and specifically the flow regime where the propagating helical vortex and stationary toroidal vortex modes become stable simultaneously and interact in the axisym-... 

MRI has been used as a non-invasive quantitative visualization technique to investigate a class of complex Taylor-Couette-Poiseuille (TCP) flows, which constitute a prototype of many mixing or fractionation processes. Here we focused on the vicinity of the Stationary Helical Vortex (SHV) regime characterized by a... 

Reactors which generate vortex flows (VFs) are common in both planktonic cellular and biofilm reactor applications due to the mixing provided by the VF. The generation of Taylor vortices in Couette cells has been studied by MRM to characterize the dynamics of hydrodynamic instabilities [56], The presence of the coherent flow structures renders the mass transfer coefficient approaches of limited utility, as in the biofilm capillary reactor, due to the inability to incorporate microscale details of the advection field into the mass transfer coefficient model. 

Dynamic filtration modules are basically of two types rotating disc filter (RDF) and vortex flow filter (VFF). In the latter, the filtration module has a cylindrical shape and has a rotating concentric cylindrical mesh in its interior. The rotational movement of the internal cylinder generates a Taylor-Couette flow in the annular gap (Roth et al., 1997), creating Taylor vortices that minimize concentration polarization and mesh fouling. Continuous perfusion processes based on this type of filter and operating continuously for up to 100 days have been reported (Mercille et al., 1994). 

Figure 9 Flow configuration of Taylor vortices in the annular gap and contours of axial velocity in the annular space from simulation for vertical and cylindrical sections of Taylor-Couette (Re = 177) and wavy vortex flow (Re = 505) (Dutta and Ray, 2004).

Taylor-Couette, 65, 67, 69, 72 trapped-vortex, 213, 214, 221 triple annular research swirler (TARS), 128 tube, 193-195, 198, 199 turbine, 141 compounds... 

The Taylor-Couette reactor (TCR), sometimes referred to as a vortex flow reactor, consists of two concentric cylinders, one of which rotates. Figure 5.23. 

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