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Blade form of static mixer and determination of parameters

May 25, 2018

The static mixer can not only achieve turbulent mixing, but also can complete the mixing of internal laminar flow. The static mixer suitable for turbulent mixing adopts the form of distorted blades, because with the increase of the flow velocity, the flow cross-section direction There will be a lot of intense eddy currents and strong shear forces. Due to the existence of such a strong shear force, the dispersion of liquids, liquids, liquids, and solids, and the dissolution of liquids and solids can be efficiently generated.


In addition to the twisted blade form, other types of static mixers may also perform turbulent mixing, but the energy of the supplied fluid is mostly consumed by the friction of the fluid with the wall surface, and there is little friction between the fluids. Therefore, from the viewpoint of energy consumption, these structures are inferior to those in the form of twisted blades.


It should be noted that the mixing form of the fluids that are mixed by the static mixer is significantly different from the mixing form that is mixed with a mixer or a mixer having a transmission member. Mixing two fluids using a static mixer is a typical laminar mixing state that results.


This mixed state changes from strip to continuous or discontinuous lines and particles, and the state change depends on the Reynolds number and Weber number when the fluid is mixed. For example, when the flow velocity, the viscosity, and the diameter of the mixer are constant, if the surface tension between the fluids is large, the mixed form of the fluid changes from a stripe shape to a linear shape, and further changes to a particle shape.


In the actual mixing process, the number and diameter of the static mixer vary with the nature of the fluid, the mixing ratio, the desired mixing state, the structural change of the liquid on the contact surface, etc., so these parameters must be determined through experimentation and experience. .


The Reynolds number is usually determined experimentally to determine the mixer magnification. However, when the Reynolds number Re<100, the mixing level and the mixing state are independent of the Reynolds number and only depend on the number of mixer units. Therefore, as long as the unified fluid is mixed, no matter how large the flow rate and the diameter of the mixer are, the number of units determined by the test is applicable.http://www.inocofiltration.com/