L = H + 0.5 * D
Verified industrial agitator designs conform to established geometric standards: Typically ranges from
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The Reynolds number determines the flow regime (laminar vs. turbulent) within the vessel: agitator design calculation pdf download verified
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Choosing the wrong impeller geometry results in excessive power consumption or inadequate mixing. Impeller Type Flow Pattern Viscosity Range (cP) Primary Application 1 – 3,000 Solid suspension, blending Pitch Blade Turbine (PBT) 1 – 10,000 Heat transfer, crystallization Rushton Turbine 1 – 50,000 Gas dispersion, fermentation Anchor / Paddle Tangential 10,000 – 100,000 High viscosity heat transfer Helical Ribbon Axial/Helical 50,000 – 1,000,000+ Highly viscous polymers 4. Mechanical Design and Shaft Sizing
For laminar flow (Re < 10):
| Step | Parameter | Verification Method | | :--- | :--- | :--- | | 1 | Process Duty | Blend time test via tracer simulation | | 2 | Impeller selection | Match Np & flow number to viscosity | | 3 | Motor sizing | Add 15-20% safety factor for seals & bearings | | 4 | Shaft deflection | Limit <0.5 mm per meter of length | | 5 | Hub key shear | Check using ASME B17.1 |
Agitation efficiency depends on matching fluid properties with the correct mixing regime. Fluid Viscosity and Behavior
(Viscosity, Density, Newtonian or Non-Newtonian). L = H + 0
), dynamic viscosity does not affect power absorption. The formula is:
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) is unique to each impeller geometry and varies based on the Reynolds number. Choosing the wrong impeller geometry results in excessive
Choose impeller type based on process needs (e.g., solid suspension, gas dispersion, heat transfer). Speed Selection: Determine optimal rotational speed ( ) based on target tip speed or pumping rate. Power Determination: Calculate Reynolds number ( ), look up ( Npcap N sub p ), and calculate shaft power (