Okra as a drag reducer for high Reynolds numbers water flows

The capability of a mixture of okra fiber and mucilage as drag reducer in high Reynolds number flows through a pipeline, in which the flux is maintained by a centrifugal pump with controlled rotation, is analyzed. A DR close to the maximum drag reduction asymptote, which is obtained for polymeric additives, was achieved when concentrations around 1600 ppm were used. The loss of efficiency of the solution over the number of passes through the system was almost the same of that observed for rigid materials like Xanthan Gum and Guar Gum, which suggest that the main cause of a decreasing drag reduction is the de-aggregation instead of mechanical degradation, commonly observed in flexible polymers. As expected, the material degrades biologically, but it seems that it is not a great problem for open systems, since such a degradation is perceptible only after 24 h. We strongly believe that this new bio-drag reducer can be an alternative to synthetic polymers or other biopolymers, since it is extremely cheap and easy to be obtained.