The mechanism of Drag Reduction

When DRA dissolves in crude oil the polymer molecules begin to uncoil and outspread as they interact with the pipeline flow. This interaction is complex, the long chain molecules dampen turbulent bursts near the pipe wall as if they were acting as tiny shock buffers. This dampening effect reduces frictional pressure loss resulting in a decrease in energy consumption or an increase in flow rate. The effect is illustrated in the figure below.