Newtonian Pressure Drop vs Non-Newtonian Prssure Drop

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

How does the viscosity of the water+xanthan gum+air change with shear? Some non-Newtonian fluids, like blood, get thinner with shear. Others, like corn starch in water, get thicker.

The flow rate will affect it also. Higher flow rate means higher shear. I suppose too you need to know if the mixture changes the friction against the tube wall.

Quote:

---

Originally Posted by vegipete

How does the viscosity of the water+xanthan gum+air change with shear? Some non-Newtonian fluids, like blood, get thinner with shear. Others, like corn starch in water, get thicker.

The flow rate will affect it also. Higher flow rate means higher shear. I suppose too you need to know if the mixture changes the friction against the tube wall.

---

The xanthan gum solution gets less viscous as the shear stress increases so, when we increase the flow rates, the shear stress increases and it will result in a small pressure drop.

Thanks