Pressure Drop Correlations of Non-Newtonian Two-Phase Flow in the Pipeline

Probably not. My understanding is that non-Newtonian fluids either get thicker or thinner when agitated.

https://en.wikipedia.org/wiki/Non-Newtonian_fluid

My non-Newtonian fluid (xanthan gum solution) gets less viscous as the shear stress increases. Thanks.

So now look at the relation of friction and pressure and let us know why you see what you see. Key word is viscosity!

Nothing beats measured data and I like that you try to confirm your results with the theory. You are almost there.

It's a linear relation.

Yes the viscosity and density dramatically drop after running the flow loop for like 20 minutes. So, the viscosity must have been less than the water viscosity to give pressure drop less than the Newtonian fluids do.

Thanks

Lots of Newtonian fluids have more viscosity than water, and a few have less.

What is the point? What two phases? solid suspended in liquid? Colloid? Foam of gas in liquid?

Your OP did not specify, but I saw later about Xanthan Gum. Does the solution go back to being "thick" are standing still a while?

How does that make you feel? What do you want to do about it?

The point is knowing if the non newtonian fluid could make pressure drops less than the newtonian fluids do at the same conditions?

The liquid is slurry (xanthan gum+water) flows with air.

Yes the solution goes to be thick again. I think the solution has a higher density than the water so, it doesn't make any sense to get less pressure drops.

Thanks

The variable quantity of gas (air) with the liquid dispersion of xantham gum should result in a fluid with less viscosity than water. By the way, density has damned little to do with viscosity.

Doubtful your nonnewtonian gum fluid mix is less viscous at the same temperature than water without the gum.

Your measured differences in pressure drop likely result predominantly from changes in fluid temperature rather than directly from shear thinning aspects.

Your pumps for the flow loop might not be developing as much head or flow rate with the mix as compared to just water. This may yield indication of less pressure drop but without taking changes in pump efficacy into account, comparison of the different pressure drop from the fluids isn't very useful.

What exactly do you need? You say you need a calculation to measure the pressure?

You either measure the pressure or you have nothing and need to calculate an estimate.

For two phase flow you are looking at a whole bunch of calculations and determinations.

You should refine your question on what you really want to do and what fluids are involved and what you have found so far.

I measured the pressure drop at the lab using the DAQ (Data-Acquisition system), and I need to validate the results by some correlations. The fluids are (xanthan gum+water)+air. I found that any two-phase pressure drop equation could work with non-newtonian flow, but I need to represent the shear stress and the velocity appropriately.

Thanks,

I take the liberty and re-post your additional information from the other post here.

Hi,
I did some experiments on Newtonian and non-Newtonian fluids measuring the pressure drop through a horizontal pipeline. The Newtonian two-phase flow was water+air and the non-Newtonian was (water+xanthan gum)+air.

I prepared 2 samples (2 concentrations) of the xanthan gum solution 1g/1L (995 kg/m3) and 2g/1L (990 kg/m3). I am wondering if it is logical that the Newtonian pressure drop was bigger than the non-Newtonian one?! Also the 2g/1L sample should've been with a higher density comparing to the 1g/1L!
Thanks

More information actually here.

Free hand calculations, unlikely. Software possible.

we work with Newtonian and nonNewtonian liquids and to figure out systems curves have used Applied Flow Technology with satisfactory success.

they do have a trial time period for the software, but I'm sure it's limited.