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Control Valves for Non Newtonian fluids

Control Valves for Non Newtonian fluids

(OP)
Good morning,

I have been looking for information regarding control valve sizing for Non-Newtonian fluids.
So far I have found a couple of proprietary methods from vendors but they are not willing to share them for study.

I am wondering if anyone knows a good reference (book, guidelines, article, website) for this topic, or even better if anyone has experience sizing control valves for such applications that can provide me with some advice.

Best!

RE: Control Valves for Non Newtonian fluids

corneliusd,

What model of non-Newtonian fluid are you wanting this for? IIRC your previous posts were for a Bingham plastic.

Good luck,
Latexman

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

RE: Control Valves for Non Newtonian fluids

(OP)
Good Morning Latexman,

So far I have been working only with time-independent Non-Newtonian. I have been able to gather enough information to estimate the friction factor for Power-law fluids, Bingham plastics, and Herschel-Bulkley fluids and now I am working on fittings, control valves, restriction orifices and pumps.

I got information to deal with normal fittings and my next step was to address the control valves but I got stuck looking for reliable references. As I mentioned in my previous post, I talked with some vendors I normally deal with to ask them about the NN, and while they can quote any valve I need they are not willing to share their basic equations. At the end this wouldn't be a problem, as we normally ask vendors to complete the final sizing anyway. However, at early stages of the hydraulics, we (process engineers) normally estimate the size and CV of the valves and use this preliminary info in our hydraulic models and datasheets.

Best regards!

RE: Control Valves for Non Newtonian fluids

There is a single reference in A. H. P. Skelland's Non-Newtonian Flow and Heat Transfer on "control valve design". DeHaven, E.S., Ind. Eng. Chem., 51, 63A-66A, No. 7 (1959). I've never looked at it, but maybe it'll help you. It seems to use a Non-Newtonian model named after the author for fluids without a yield stress, and assumes zero wall slip. DeHaven worked with non-slurry, pseudo-plastic fluids at laminar flow.

Good luck,
Latexman

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

RE: Control Valves for Non Newtonian fluids

(OP)
Good morning Latexman,

Thanks a lot for the reference. I will look for this book in the library.

Best regards.


RE: Control Valves for Non Newtonian fluids

(OP)
For anyone interested:

I talked with other vendors regarding this topic and one of them told me that basically they use the same equations as per incompressible flow, and apply viscosity corrections (apparent viscosity).

Best!

RE: Control Valves for Non Newtonian fluids

That is an interesting approach since all of the incompressible-flow equations assume a linear stress/strain relationship and the viscosity values are based on time-averaged data (that would lose the threshold stress for flow). Those equations look to me like the time honored "we have an equation, let's be careful not to look at the underlying assumptions and boundary conditions". I don't have an alternative, but I certainly don't use the D'Arcy-Weisbach for emulsions.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

RE: Control Valves for Non Newtonian fluids

My 6th Ed. of Perry's has a fair amount of information and references on "additional frictional loss for laminar flow", and laminar slow flow (NRe < 1), through valves, fittings and junctions. Have you looked in Perry's? A corrected Reynolds number is all I know to do too.

Good luck,
Latexman

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

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