Viscosity measurement with a coriolis meter 1

[Michael Mayer]

I am currently measuring the viscosity of a non-newtonian fluid (shear thinning) with a coriolis meter. The client measures the viscosity using a fann 35 viscometer at a shear rate of 300 reciprocal seconds. How can calculate the shear rate of my entire system so I can display viscosity at 300 reciprocal seconds?

 

[SuperSalad]

It should be the fluid velocity divided by the dimension of your flow meter orifice (diameter?) which will give you the shear rate. Then adjust the speed to obtain a shear rate of 300 s[sup]-1[/sup] to obtain similar results as the client.

Andrew H.

http://www.mototribology.com

 

[Michael Mayer]

Would I not need to take the shear rate of the rest of the system (piping, valves, elbows) into account? Also, the coriolis meter uses a torsional method to calculate the viscosity, would this not also affect the shear rate?

 

[Latexman]

If the fluid viscosity exhibits no time dependency (i.e non-thixotropic), no. With no time dependency, non-Newtonian behaviors are (assumed) instantaneous.

For a Newtonian fluid, shear rate at the wall of a pipe (circular conduit) = 8v/d. For a non-Newtonian fluid it depends on the rheology model, but it's usually close to 8v/d.

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.