- #1

physicophile

- 19

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I have a quick question for you. I have small sample of a cement-like-like-material and I am high shear mixing it using a power drill and a impeller blade. The material is placed a beaker and the impeller blade shears the cement of the bottom of the beaker.

__I would like to calculate the amount of shear I am imparting upon the cement while I am mixing it.__

The impeller is shaped like a upper case T

__Please tell me if I am approaching my problem in the correct manner.__

Shear = F/Area

Force = Mass*Acceleration

Acceleration = (v)^2/r

V=(w*r)

w= RPS/(2*PI)

Therefore the shear force on the cement is ([tex]\int[/tex] mass *acceleration)/(area of impeller) = mass/(area of impeller)*[tex]\int[/tex] ((w*r)^2/r) = mass/(area of impeller)[tex]\int[/tex] (w^2*r^2)/r = w^2*mass/(area of impeller) [tex]\int[/tex] r^2/r

= w^2*mass/(area of impeller) [tex]\int[/tex] r = r^2*w^2*mass/(area of impeller)

The area of shear is the area of the bottom of the impeller in contact with the beaker, the cement is being mixed in.

Thank you very much for your help.