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Old   August 7, 2003, 04:12
Default Rheology Question
  #1
JamCam
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Sorry, but this question is not related to CFD, but I know this forum can be very helpful. To calculate K, the consistency factor for Power Law fluids from shear stress (Dynes/cm2) and shear rate (sec-1) readings, you use this equation:

K = 100*shear stress @ 300rpm / shear rate @ 300 rpm^n

n = the Power Law exponent

This gives K in centipoise. I see many people use eq. cp or Pa.s^n. What are these units?! How can I convert centipoise to eq.cp or Pa.s^n

Any help gratefully appreciated!

JC
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Old   August 7, 2003, 05:47
Default Re: Rheology Question
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Tom
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Hi,

If you visit www.efluids.com you will find a Unit Conversion Calculator. Perhaps that is helpful.

Tom
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Old   August 7, 2003, 06:13
Default Re: Rheology Question
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JamCam
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Thanks for the reply, unfortunately I've tried many a conversion calculator, with no mention of eq. cp or Pa.s^n. I'm sursprised at the lack of information in books and on the web about this. I just need something that explains the difference to me!

JC
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Old   August 7, 2003, 06:46
Default Re: Rheology Question
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Andreas
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Hi Jam As far as I know, centipoise (cPs) is an obsolet unit for viscosity.

1 Pa*s = 1000 centipoise

Bye Andreas
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Old   August 7, 2003, 06:57
Default Re: Rheology Question
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JamCam
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Thanks,

I know centipoise is a bit obsolete, the preferred SI unit is indeed Pa.s (the same as N.s.m2 and kg.m.s).

It's when we're dealing with consistency factor K and flow behaviour index, n that eq.cp or Pa.s^n appears. It has something to do with this, but I don't know what!

For online conversion, you can't beat this site:

http://www.ex.ac.uk/cimt/dictunit/dictunit.htm

but there's no mention of what I'm after here!

JC
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Old   August 11, 2003, 08:01
Default Re: Rheology Question
  #6
Pete
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You'll be surprised how much we use centipoise in industry!
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