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How to choose a mixer for different medium viscosity

by:BOQU     2023-04-14
Viscosity refers to the fluid's resistance to flow, which is defined as: when the liquid flows at a speed of 1cm/s, the shear stress required on each 1cm2 plane is called dynamic viscosity, and the unit is Pa s. ×Viscosity is a property of a fluid. When the fluid flows in the pipeline, there are three states of laminar flow, transitional flow, and turbulent flow. These three flow states also exist in the stirring equipment, and one of the main parameters that determine these states is the viscosity of the fluid. During the stirring process, it is generally considered that the fluid with a viscosity less than 5Pa s is a low-viscosity fluid, such as: water, castor oil, maltose, jam, honey, lubricating oil, heavy oil, low-viscosity emulsion, etc.; ××5-50Pa s is a medium-viscosity fluid , such as: ink, toothpaste, etc.; 50-500Pa s for high-viscosity fluids, such as chewing gum, plastisol, solid fuel, etc.; × greater than 500Pa s for ultra-high-viscosity fluids such as: rubber mixture, plastic melt, silicone wait. ×For low-viscosity medium, a small-diameter high-speed agitator can drive the surrounding fluid to circulate and reach a distant place. This is not the case for fluids with high-viscosity media, which need to be directly driven by a stirrer. The impellers suitable for low-viscosity and medium-viscosity fluids include paddle type, open turbine type, pusher type, long thin blade propeller type, disc turbine type, Bruma gold type, plate frame paddle type, three-blade backward curved type, MIG formula etc. The impellers suitable for high-viscosity and ultra-high-viscosity fluids include ribbon impeller, screw type, anchor type, frame type, propeller type, etc. The viscosity of some fluids changes with the progress of the reaction, so it is necessary to use an impeller suitable for a wide range of viscosity, such as a universal impeller. 1 poise (P) = 0.1 Pa*second (Pa*S) 1 centipoise (CP) = 0.01 poise (P) = 1 mPa*second (mPa*S) 1Pa.s=1N.s/m2=10P poise =10 to the third power cp=1Kcps The ratio of the dynamic viscosity of the liquid to its density at the same temperature is the kinematic viscosity. unit was"Si"(St), the practical unit is"cist"(cSt). The following formula can be used to convert to the previous legal unit of measurement: 1 Si (St) = 10-4m2/s1 Centis (cSt) = 1mm2/s
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