Effect of salt on turbulent drag reduction of xanthan gum

• Xanthan gum (XG) is applied as a turbulent drag reducer.
• Turbulent drag reduction is studied using a rotating disk apparatus.
• Mechanical degradation of XG under a turbulent flow is examined using model equation.
• KCl salt is found to affect turbulent drag reduction efficiency of XG.

The turbulent flow of an aqueous KCl solution driven by a rotating disc in a closed chamber showed significant drag reduction (DR) when a small amount of xanthan gum (XG) was added. The effects of the experimental parameters (XG and KCl concentrations, and time) on the drag reduction efficiency were examined. While the DR efficiency of XG decreased with increasing salt (KCl) concentration, the time-dependent DR efficiency was found to be fitted well using Brostow model equation.