Vortex generator

Figure 6 Flow along a simulated surface roughness (protrusion type) at Re 0.02, visualized using aluminum powder. Note the vortex generated downstream of the cube. Flow is from left to right as indicated by the arrow (added by the author). Source Adapted from Ref. 13, Sec. 12.1 (original by Taneda S. J Phys Soc Jpn 1979 46 1935).

Mi, J., and G. J. Nathan. 1999. Effect of small vortex-generators on scalar mixing in the developing region of a turbulent jet. Int. J. Heat Mass Transfer 42 3919-26. 

Swirl-flow devices include a number of geometric arrangements or tube inserts for forced flow that create rotating and/or secondary flow inlet vortex generators, twisted-tape inserts, and axial-core inserts with a screw-type winding. 

M. Fiebig, Vortex Generators for Compact Heat Exchangers, J. Enhanced Heat Trans., Vol. 2, pp. 43-61,1995. 

Fig. 2.22. An extrusion head with Cl vortex generator (a) mechanical and (b) vortex generators...

In Germany, the DLR Institute of Aerodynamics and Flow Technology has been involved in research on the impact of tubercles on the performance of helicopter blades. In fact, the research has already resulted in a patent on Leading-Edge Vortex Generators, and the invention has been used to design and build various experimental helicopter blades, which are undergoing tests. If all the results of these tests are positive, as it is expected, a... 

Bender, E., B. Anderson, and P. Yagle. 1999. Vortex Generator Modeling for Navier-Stokes Codes. ASME Paper No. FEDSM99-69219. 

Kalashnikov, V.N. Kudin, A.M. Ordinartsev, S.A. Influence of polymeric additives on the vortex generation in the wakes of thin cylinders. DISA Information, No. 19 1976. 

Saturated feed gas enters a vortex generator to induce swirl before it is cooled adi-abatically, condensing out the moisture, in a Laval nozzle. The cooled gas/liquid (or fine droplets) mixture is subjected to increased swirl in the nozzle which generates g forces of about 500 OOOg, whereupon the liquid is bled off with slip-gas before the bulk of the now dry gas is diffused to dissipate the kinetic energy and increase the static pressure at the exit. The separation efficiency is typically 95%. 

Several mixing technologies are commercially available. Depending on the reductant injection, two general types of mixers can be defined (a) Mixers for secondary atomization combined with small scale turbulence for droplet breakup and (b) swirl or vortex generators for large scale distribution [31, 33]. 

Dynamic gas washer, according to Figures 7.1 and 7.2, contains the vertical cylindrical case with the bunker gathering slime, branch pipes of input and an output gas streams. Inside of the case it is installed conic vortex generator, containing. 

A vertical mixing tank (Figure 7-31) is fit with baffles at the walls to break the vortex generated by the agitator. A certain gap is left between the baffles and the wall of the tank. 

Lin J. (1999) Control of turbulent boundary-layer separation using micro-vortex generators. ALAA paper 99-3404. 

Lin J. (2002) Review of research on low-profile vortex generators to control boundary-layer separation. Prog Aero Set 38 389—420. 

The presence of baffles can improve the flow pattern in certain conditions elimination of vortex, enhancement of turbulence, and so forth. The impeller position in the tank can modify the flow pattern The off-center position can avoid vortex generation. Agitator shafts can be mounted through the wall in very large tanks (>20 tons) to avoid a vortex when there is no baffle. 

Provide a length of empty pipe downstream of a vortex-generating device to achieve bulk mixing. 

At low L/D there is some deviation as the flow develops, but this is usually neglected because there is also little mixing. The Kenics HEV shows a weak Reynolds number dependence (Figure 7-18), along with a length/number of element dependence. This vortex-generating mixer design is typically applied at a Reynolds numbers above 10 000. 

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