anchor agitator
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Analyses of Dynamical Systems Structures and Mixing Patterns in an Anchor Agitator

2018 ◽  
Vol 51 (2) ◽  
pp. 136-142 ◽  
Author(s):  
Hae Jin Jo ◽  
Hye Kyeong Jang ◽  
Young Ju Kim ◽  
Wook Ryol Hwang
Keyword(s):  
Dynamical Systems ◽  
Mixing Patterns ◽  
Anchor Agitator

scholarly journals CFD study of the thermal transfer of a non-Newtonian fluid within a tank mechanically stirred by an anchor-shaped impeller

2018 ◽  
Vol 180 ◽  
pp. 02089
Author(s):  
L. Rahmani ◽  
O. Seghier ◽  
A. Benmoussa ◽  
B. Draoui
Keyword(s):  
Newtonian Fluid ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Thermal Fields ◽  
Thermal Transfer ◽  
Finite Volume Discretization ◽  
Mobile Anchor ◽  
Anchor Agitator

The most of operations of chemical, biochemical or petrochemical industries are carried out in tanks or in reactors which are mechanically-controlled. The optimum mode of operation of these devices requires a finalized knowledge of the thermo-hydrodynamic behavior induced by the agitator. In the present work, the characterization of the incompressible hydrodynamic and thermal fields of a non-Newtonian fluid (Bingham) in a flat, non-baffled cylindrical vessel fitted with anchor agitator was undertaken by numerical simulation, using the CFD code Fluent (6.3.26) based on the finite volume discretization method of the energy equation and the Navier-Stokes equations which are formulated in (U.V.P) variables. We have summarized this simulated system by comparing of the consumed power and the Nusselt number for this type of mobile (Anchor agitator).

Process viscometry in flows of non-Newtonian fluids using an anchor agitator

2017 ◽  
Vol 29 (4) ◽  
pp. 317-323 ◽  
Author(s):  
Hae Jin Jo ◽  
Hye Kyeong Jang ◽  
Young Ju Kim ◽  
Wook Ryol Hwang
Keyword(s):  
Newtonian Fluids ◽  
Anchor Agitator

Apparatus with Intracyclic Variation of the Velocity of the Anchor Agitator

2016 ◽  
Vol 52 (5-6) ◽  
pp. 379-385 ◽  
Author(s):  
N. N. Torubarov ◽  
R. M. Malyshev ◽  
M. V. Serov
Keyword(s):  
Anchor Agitator

A Numerical Model of Yield Stress Fluid Dynamics in a Mixing Vessel

2002 ◽  
Vol 12 (4) ◽  
pp. 182-191 ◽  
Author(s):  
M. Marouche ◽  
D. Anne-Archard ◽  
H. C. Boisson
Keyword(s):  
Yield Stress ◽  
Laboratory Experiments ◽  
Numerical Study ◽  
High Yield ◽  
Laminar Regime ◽  
Carreau Model ◽  
Global Power ◽  
2D Flow ◽  
Anchor Agitator ◽  
Shear Thinning Fluid

Abstract A numerical study is conducted on the behaviour of yield stress fluids in a mixing vessel equipped with anchor agitator in laminar regime. It is shown that extending a standard Carreau model of shear thinning fluid is a suitable practice. Validations versus Couette flow analytical solution are satisfactory. Main features of local hydrodynamics and global power consumption are described for a 2D flow. Significant changes in the flow pattern are observed for low inertia and high yield stress and the results are considered as guidelines for further laboratory experiments.

Fig. 12 Radial (Rushton) type impeller. blade angle, it is best to work closely with the manufacturers of the mixer to specify an optimum design for the process. The preceding discussion of axial- and radial-flow turbines has been a very cur-sory survey of what can be a very involved and detailed study. As mentioned above, a large amount of research on these types of mixers is available [13,14]. A detailed dis-cussion of this subject would be beyond the scope of this work. If a blending or sus-pension problem occurs in large production batches, consultation of the references on mixing included at the end of this chapter or, even better, consulting the experts at the major manufacturers of this type of mixer, would be the best place to start. 3. Anchor Mixers An often overlooked mixing device, which is low speed and considered low capabil-ity, is the anchor agitator, so named for its anchorlike shape, as illustrated in Fig. 13. However, this slowly moving agitator makes it possible for many dispersion and emul-sification processes to be accomplished without overshear, aeration, and heat transfer problems. The anchor agitator is a slow (up to 50 rpm) device whose sole function is to rotate the contents of a batch in a radial direction without providing any significant shear. These are high-torque devices that must be designed sturdily to withstand the forces of the high viscosities. Anchor agitators are typically designed to be able to withstand a maximum viscosity beyond which they might actually bend or break. That is, the an-chor itself is built of materials strong enough to withstand the drag of the viscous liq-uid as it passes by the mixer. In addition, the motor has to supply the very high torque requirement that arises when the anchor is stirring viscous materials. When designing the mixer it is important not to understate the viscosity. This is especially important if there is a point in the process where the anchor must be stopped. If this happens, in the case of shear thinning materials, the agitator has to start up from rest in a viscosity much higher than that normally occurring during the process. Products exhibiting pseudoplastic or Bingham plastic behavior are very difficult to move when at rest.

1998 ◽  
pp. 338-339
Keyword(s):  
Plastic Behavior ◽  
Impeller Blade ◽  
Bingham Plastic ◽  
Start Up ◽  
Preceding Discussion ◽  
Large Production ◽  
High Torque ◽  
Anchor Agitator ◽  
Transfer Problems ◽  
Very High

without producing any appreciable velocity differences, so that almost no mixing oc-curs. By installing a stationary baffle, some mixing capability is added. This works well on materials with viscosities from 5000-25,000 centipoise. For the best results, with products between 100,000 and 250,000 centipoise, a counterrotating set of crossbars provides excellent blending. Such equipment is illustrated in Fig. 15. Some designs use the same motor, turning a pinion gear between two opposing bevel gears to provide rotation in opposite directions. Others provide a greater degree of flexibility by driving the two shafts on separate motors. In either case, there will be a hollow shaft driving the anchor agitator and an additional shaft located inside the hollow shaft to drive the inner crossbars [21]. B. High-Speed Dispersers A simple yet powerful device used extensively in industries other than pharmaceutical manufacturing for dispersion of solid particles in liquids is the high-speed disperser. Sometimes called a saw-blade disperser for the shape of the mixing impeller, this ma-chine consists of a variable-speed shaft connected to an impeller with a serrated edge. The mixer is designed to rotate at a high speed in order to produce shear and pumping (Fig. 16). This type of equipment is designed specifically to disperse powders, usually pig-ments, into liquids. Much has been written that high-speed dispersers are capable only of dispersing "easy" pigments [23]. This is true if the particles are hard agglomerates or individual hard particles with some strength. Furthermore, the high-speed disperser design is ineffective if the viscosity is low. The only shear stress that is delivered to Darticles is due to the hydraulic shear that is a product of the shear rate and the viscos-Fig. 15 Counterrotating agitator. (From Ref. 21.)

1998 ◽  
pp. 341-341
Keyword(s):  
Shear Stress ◽  
High Speed ◽  
Solid Particles ◽  
Hollow Shaft ◽  
Bevel Gears ◽  
Hard Particles ◽  
Pinion Gear ◽  
Hydraulic Shear ◽  
Saw Blade ◽  
Anchor Agitator

Fig. 14 Scraped-surface anchor agitator with auxiliary crossbar agitator. (From Ref. 20.) have many deleterious effects on it. First, the emulsion may have components that cannot stand the wall temperature, which may be as high as 110-125°C. This is even more important if the dosage has active ingredients that decompose at these temperatures. Second, if the temperature is hot enough, the product may actually stick or burn on the sidewall. Cooling of product through sidewall heat transfer can cause almost as many prob-lems as heating. During cooling, the viscosity of a product almost always increases. A viscous product that is not physically removed from the sidewall builds up and forms an insulating layer than resists efficient heat transfer. Again, once this condition oc-curs, it is very difficult to reverse it. There is a variety of different designs of scraper blades. Some are arranged in rows. Some are offset on either side of the anchor, allowing some overlap as an an-chor makes a complete revolution. Some actually are designed to allow the anchor to revolve in opposite directions, which can prevent the buildup of product on the fol-lowing edge of the anchor. Some designs use a spring to force the blade against the wall. Most modern designs use the force of the liquid flowing into the blade to bring it close to the wall. Scraped-surface agitators are definitely required in emulsification equipment where heat transfers are necessary. These anchor agitators with scraping blades can be just as simple anchors or part of complex multishaft mixers. 5. Counterrotation Anchor-type agitators have a decided weakness when handling high-viscosity products of more than about 75,000-100,000 centipoise. They tend to rotate only the product,

1998 ◽  
pp. 340-340
Keyword(s):  
Heat Transfer ◽  
Wall Temperature ◽  
High Viscosity ◽  
Active Ingredients ◽  
Insulating Layer ◽  
Complete Revolution ◽  
Efficient Heat Transfer ◽  
Anchor Agitator ◽  
Heat Transfers

The Effect of Scalling-Up and Hydrodynamic Properties of Stirring System on the Kinetics of Vegetable Oil Hydrogenation

1993 ◽  
Vol 58 (2) ◽  
pp. 320-327
Author(s):  
Ivan Dědek
Keyword(s):  
Reaction Kinetics ◽  
Reaction Rate ◽  
Specific Effect ◽  
Scaling Up ◽  
Point Of View ◽  
Geometrical Parameters ◽  
Hydrodynamic Properties ◽  
Anchor Agitator ◽  
Kinetics Of ◽  
Limiting Value

The stirring system of classical turbine agitator beside the anchor agitation system was studied from the point of view of the effect of their hydrodynamic properties on the kinetics of sunflower oil hydrogenation, It was found out that the anchor agitator makes up a higher gas hold-up than the turbine one and its efficiency from the view of reaction kinetics is higher. On changing the geometrical parameters of anchor agitator - by reducing its blade height - its hydrodynamic properties change considerably, and its efficiency decreases. The scaling-up of the stirring system did not manifest itself in the reaction rate in case of the turbine agitator. With the anchor agitator, the scaling-up resulted in the confirmation of its specific effect on the reaction kinetics, viz., on exceeding the limiting value of stirring frequency, the dramatic loss in efficiency took place.

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