During mixing using a rushton impeller, the flow is accelerated in a radial direction and deflected at the vessel wall into an upper and lower recirculation. The effect of the chopper on granules from wet highshear. The sbh series, like the sb, is based on the lf series pump design and offers. Homogenizer high shear 3d cad model library grabcad. Fluid mixing is a key operation in the design of many processes.
Main street, palmyra, pa 17078, usa abstract hydrofoil impellers are considered to be low shear devices. Effects of viscosity, nonnewtonian shearthinning index, agitator design, and scaleup on shear rates. Design strategy for the optimization of the impeller in an axial. Selecting the right agitator impeller is crucial for mixing efficiency. Morehousecowles impellers are also available for dissolvers made by other manufacturers. The required high local shear forces are thereby achieved by high circumferential speeds in a. The axial flow turbine is a classic medium shear impeller. A series of aggressive blades coupled with a high powered mixer mean these impellers can withstand the toughest of mixing tasks. We offer the widest selection of impeller designs in sizes from 2 to 36 in diameter. Wide range of specific speed design different types of impellers in a specific speed. Hsd800 thecowles high shear disc impeller creates highshear to prevent clumping, wet out powders, reduce particle size and emulsify. What are the best software suited for design and analysis. In recent decades, threeblade impellers have been wellestablished in pharmaceutical highshear granulation.
An industrial impeller needs a high flow number and power number higher than. These axial mixing blades will draw more power per volume than the propellers or hydrofoils as motor power is converted to shear energy. Highest granule strength was achieved using a stainless steel power whisk. Some designs have been developed specifically to perform well in laminar flow applications and even in high shear mass transfer processes. In our article on 4 impeller types and their applications, we provided an overview on the most common types of impellers used in industrial mixing. Discover pump blade design optimization software and create breakthrough impeller. Spx flow uses cfd software to develop a lasting highly functional industrial mixing. The product container had a volume of 10 l with an inner diameter of d m 0. Due to its high importance, we have invested many resources in this critical component. Depending on the design, these high shear mixers can either be bottom or top driven units. Cfd study of the flow induced by a grooved highshear impeller in. The shear rates at the blade surfaces were calculated using eq. The design of a centrifugal impeller must yield blades that are aero dynamically efficient.
Granule growth combined with the high shear forces from the impeller formed compact and spherical granules. Nicomac high shear mixer granulator, can be provided with both automatic and manual dosing system for powders or binding solution. Mixer agitator mixtank calculators white mountain process. Homogenizer high shear for mixing creams, ointments, sauces, flavoring emulsions and pharmaceutical suspensions. This reference agitator sizing calculator is a great guide for folks to do estimated mixtank calculations to figure out the desired mixer hp horsepower, what agitation flow rate and tank turnovers per minute or pumping rate is available, impeller tip speeds, and other output data that is useful in mixing selections. The particle trajectories are nontrivial due to recirculation regions resulting from the use of mixing impellers. But i will go with axstream because of its purely for turbomachines and best for shrouded. Star shaped impeller having tapered blades provides intermediate shear levels. The median particle size was determined based on the total yield recovered and therefore includes fines, granules, and any oversized agglomerates. Due to its high shear levels, this stirrer is primarily used for blending, improving heat transfer, and gas dispersion processes. When the impellertotank diameter ratio exceeds 50%, a typical high efficiency impeller loses mixing effectiveness.
Accept nothing less than genuine morehousecowles impellers. Everything you need to know about pump blade design optimization. Highshear impellers convert the majority of the energy of the motor to shear force. However, threeblade impellers often require high rotation speeds to initiate product circulation and to provide proper granulation performance. The screw impeller is suitable for fluids which are not too pseudoplastic with power law. Grof publisher elsevier source advanced powder technology keywords breakage, compaction, composite packings, force chains year 2016. While for the horizontal high shear granulator, the impeller shaft rotates in the horizontal mode or by its sides. The analysis of impeller shape performance was carried out with the sst shearstress transport model coupled with the streamline curvature turbulence model. Another pump weve found best suited from this in these applications is the sanitary twin screw pump. Saw tooth impeller generates heavy turbulence in the area around the impeller. Its devided in number of features within one platform like preliminary design, optimization, flo. Their unique design significantly reduces dissolving time. Because of the simple design, it is also very cost effective in large applications and high viscosity applications. For example, figure d1 shows a high specific speed, mixed flow, 2.
Start shape impeller is used in polymerization reactor. The rushton impeller is a high speed radial flow impeller. Pdf design and analysis of centrifugal pump impeller for. The simple design of this impeller provides a combination of both radial and axial flow, generates high shear levels, and provides excellent mixing ability while providing easy cleanup. The r510, a bar turbine, provides high shear while developing. The shear is generated between the rotor and an innovative and optimized perforated. Whether an application requires flow, gas dispersion, chemical reaction, solids suspension or a combination of all four, there is a sepro mixer agitator. However, simply spinning the impeller at high speeds to ensure a wellmixed vessel isnt always the best plan of attack, said luke munholand technical services engineer at ansys inc. They typically give high shear rates because of their angle of attack.
Impact of impeller design on highshear wet granulation. For high viscosity blending, using a low shear impeller keeps fluids at a uniform viscosity in the blending tank. Outlet velocity of perpendicular component versus time for a310, a200, and r100 impellers. The number of blades, and tip chord angle can be varied to meet your process requirements.
Scaleup effects on flow patterns in the high shear mixing. Outlet velocity of main velocity component versus time for a310, a200, and r100 impellers. A screw impeller produces effective high viscosity blending of shear sensitive polymers. Our goal was to enhance our existing rotosolver design and make it even better, offering processors a significant improvement in. It is only employed to optimally design the higher specific speed impellers of mixedflow pump and runners of. Estimation of agitator flow shear rate wu 2006 aiche. Laser velocimeter taking velocity measurements of a mixing impeller. Cfd software paired with parametric design optimization. Design method, impeller, low specific speed centrifugal pump, numerical simulation. For the case of horizontal high shear granulator machines, the design of the impeller is such that the rotation is in a horizontal plane.
Easily simulate a stirred reactor to ensure even solids. Impact of impeller design on highshear wetgranulation. Effect of impeller design on homogeneity, size and. A highshear mixer disperses, or transports, one phase or ingredient liquid, solid, gas into a main continuous phase liquid, with which it would normally be immiscible.
The high shear blending capability of the sbh is facilitated by the greater number and expanded rows of rectangular shaped teeth with radial slots for the highest shear possible. The packo shear mixer pump is mainly used for inline mixing, homogenisation and dispergation applications. The ansys cfx software was chosen for the numerical cfd results. The primary challenge was learning how to use blood as a working fluid because burgreens background was in aerospace engineering designing aircraft wings where he was used to working with compressible fluids.
Investigations were performed in a laboratory highshear granulator mycromix, bosch packaging technology, schopfheim, germany, as illustrated in fig. Impact of impeller design on highshear wet granulation authors c. The optimal hydraulic design of centrifugal impeller using genetic. What is pump shear and what can we do to minimize it in. The r500 typically requires an additional impeller a310a200 to provide the necessary flow to blend the tanks contents.
Mixerdirect uses three grades for its highshear blades. These kind of blades also known as cowles mixer blades excel at quickly breaking down solids and producing a fine grind. Impeller design had a significant impact on high shear granulation. The aflr3 software gave us a high enough quality mesh so that whenever i deformed it, we retained high quality elements. Issn 1 7467233, england, uk world journal of modelling and simulation vol. The bottom drive granulator featured a replaceable impeller that rotated between 0 and 500 min. A novel approach to protein recovery a high shear impeller is used for stirring and critical values for the impeller speed must be exceeded to create these stable gas liquid dispersions typically 5000 rpm. Sepro mixing applies experiencebased knowledge and technical expertise to high quality fluid mixing systems for use in mining, chemical, pharmaceutical, paper, and water treatment industries. Design of a low shear hydrofoil through the use of. The software code xfoil was used to illustrate typical distributions of the shear rates along the blade surfaces. This research is financially supported by the national key basic research program of china.
Now well go into more detail about each impeller type and their influences on the mixing process. Despite the importance of this type of mixers in many industrial processes knight et al. For low viscosity blending, material densities, shear characteristics, and blend time are the most important factors in agitator impeller design and selection. Mixer design not only includes optimizing the impeller design but also includes mechanical design, tank structural design, tank internals design i. Unlike axial impellers, radial impellers are commonly selected for low level mixing known as a tickler blade or elongated tanks. The impeller proposed in that contribution has mechanical and design problems. For this reason, high shear impellers operated at high speed are used, yielding a high energy consumption. Very effective in both low viscosity and high, this axial mixing blade allows a mixer to the break up agglomeration and impart solids effectively. Other pumps with a reputation for low shear include progressive cavity, eccentric disc, and sine pumps. A rotor or impeller, together with a stationary component known as a stator, or an array of rotors and stators, is used either in a tank containing the solution to be mixed, or in a pipe through which the solution passes, to. Nataraj2 1 mechanical engineering, karpagam college of engineering, coimbatore, india 2 mechanical engineering, government college of technology, coimbatore, india received june 27. Gentlewing mixer is a new vertical highshear mixergranulator in which the classical threeblade impeller exchanged with a novel twoblade impeller with elongated wings as shown in figure 1 10. Impact of impeller design on highshear wet granulation authors f. Register and download cfturbo software for a free trial today.
How computational fluid dynamics is applied to mixer design. Although blending is generally good, heat transfer is not as good as the close clearance high viscosity impellers. The bowl geometry is optimized to permit working volumes from 3090% of full capacity. The nicomixer line of granulating equipment combines 3blades impeller with design able to ensure a very good movement of the granules even at low speed. Schmidt publisher elsevier source powder technology keywords dia, doe, gentlewing, high shear wet granulation, threeblade year 2016. Different cover and impeller sets are available for varying application requirements. A chopper was mounted in the upper lid with speeds of up. Shear rate variation with power number power, flow, and impeller outlet shear rate data were measured in a t390 tank operating in water, tank diameter 390 mm, impeller diameter 160 mm, impeller to tank bottom distance mm, water level 400 mm. The chemineerscs impeller features an advanced design that produces flow characteristics of much larger impellers, without the added weight or. High shear impellers are designed to break down tough solids into a homogeneous solution. Study on the design method of impeller on low specific speed. The r500 is a sawtooth impeller providing the highest shear of any impeller available. Highshear impellers hsis are mixers used in industrial stirred tanks to incorpo. The design parameters of the impeller were calculated using the empirical equations found srinivasan.
To promote good fluid flow, high shear impellers are often coupled with an axial flow impeller. Blindly increasing impeller velocity is power intensive and will create high shear stresses. High shear impellers are operated at high speeds and are generally used for addition of the second phase. High temperature flexible beater was the best in terms of yield and homogeneity. Given design parameters, the desired optimal centrifugal impeller can be. The high shear granulator is a state of the art equipment which has got some of the notable features to enhance its operations. They also have a relatively low pumping number, making them the most sensitive to viscosity.1055 1115 365 1236 447 104 1185 330 849 1309 566 1516 847 893 1408 630 402 1085 1084 1658 783 1590 858 240 286 1042 898 118 874 1341 207 1011 1283 459