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# Bingham Plastic Generalized Equation

## Bingham Plastic Generalized Equation

(OP)
Good morning,

I have been reading the equations provided by Darby (Chemical Engineering Fluid Mechanics 2nd Ed) to estimate the friction factor for Bingham plastics in both laminar and turbulent flow.

The generalized method suggests a combination of the laminar and turbulent friction factor as follows:

f = (fl^m + ft^m)^(1/m)
m = 1.7 + 40,000/Re

However, I noticed that when using this equation I get different results than using just the laminar or turbulent equivalent, and more over, the resulting f is bigger than both laminar and turbulent.

I am wondering if there is any update to this expression in further editions, or if there is something I am missing.

Thanks a lot,
CD

### RE: Bingham Plastic Generalized Equation

Though I am not familiar with the complications re flow with non newtonian fluids, there is detailed discussion of friction factors, flow etc for Bingham plastics and others in Perry Chem Engg Handbook, 7th edition, pages 6-13 to 6-14.

### RE: Bingham Plastic Generalized Equation

CD,

According to Amazon, the 3rd Edition is not available yet. They are taking a price guaranteed pre-order for, what looks like, a release date of December 28, 2016. It's ~ \$100. They claim shipping is free. LOL!

Have you downloaded the Errata 2ndEd-2.pdf on CRC website? If not, I'll upload mine for you. See attachment below. There was an error close to the pages you are using, but you may have figured it out.

Good luck,
Latexman

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

### RE: Bingham Plastic Generalized Equation

(OP)
Good morning,

georgeverghese: Thanks a lot for your advice. Honestly I haven't thought of this reference. I will take a look at it.

Latexman: Yes, I caught both errors when checking the equations but thanks for the information. It will help me a lot for other sections I haven't read so carefully.

Best!

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