DRAG REDUCTION STUDY ON XANTHAN WATER SOLUTION AND XANTHAN OIL SOLUTION

Drag reduction using polymer additive in fluid flow is an interesting phenomenon in turbulent pipe flow which was discovered by Tom back in 1948. Due to its industrial importance, this subject have been undergoes extensive studies both in experimental and in theoretical domain. In practice, it has been observed that drag reduction as much as 90% has been achieved using higher molecular weight of certain flexible polymer at low concentration of 20 ppm. In this paper, the degree of drag reduction of biopolymer, xanthan gum in water and oil is examined by measuring the value of fanning friction factor. This is done by left the solution to flow inside the flow loop and the pressure drops and flow rate are measured. The effect of concentrations at 0.05wt% and 0.1wt% and polymer chain network on the level of drag reduction was examined. The hydraulic conditions were varied from pumping operation of 5Hz to 28 Hz.
Overall, the results show that the degree of drag reduction increases with increasing in polymer concentration and Reynold number. The percentage of drag reduction is measured to be within 20% to 30% for 0.05wt% and 90% to 98% for 0.1wt%. The level of fluctuation in turbulence of the fluid flow is observed to decrease as the polymer is introduced into the flow. At constant pumping operation, increasing in polymer concentration resulting in decreasing in value of Reynold‟s number.
The results also agree with the theory of polymer chain network in the degree of drag reduction. It is observed that pseudo homogeneous solution of 0.05wt% exhibit a much lower value in fanning friction factor compare to homogeneous solution of 0.05wt% at the early of the experiment. As the time increase, the polymer chain networks are subjected to the repeated shear stress resulting the distance between the polymer molecule distances to increase until it is equally distributed as in homogeneous solution. Resulting the value of fanning friction factor in pseudo homogeneous solution to decrease until it reached almost the same value of fanning friction factor in homogeneous solution.