Calculating Shaft Natural Frequency in Free Air and Liquid

AI Thread Summary
Calculating the natural frequency of shafts in mixing tanks can vary significantly between free air and liquid environments. Most literature focuses on free air calculations, while limited resources address the effects of liquid, which introduces damping. The best method depends on operational conditions; if a mixer shaft may run in low or no liquid, calculations should prioritize air conditions to account for worst-case scenarios. Understanding these differences is crucial for accurate engineering assessments. Properly evaluating both environments ensures optimal design and functionality of mixing equipment.
Christoffer28
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Hello Fellow members.

In many litterature about mixing liquids in tanks, they describe how to calculate the natural frequency of shafts in free air.
But i have only found one book that describe about natural frequency of shafts in liquid, and it should have a damping effect of the natural frequency.

The question is: What is the best method? to calculate the frequency in free air or in liquid?Thanks in advance.
Christoffer
 
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Welcome to PF.

Christoffer28 said:
What is the best method? to calculate the frequency in free air or in liquid?
If the mixer shaft might be operated, even only once, while there is no, or low, liquid in the tank, then it must be calculated for air.
 
Ok, so its a question of dimensioning a worst case scenario.

Thanks for the answer :)
 
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