Drag reduction and solvation in polymer solutions

A model is described which explains drag reduction (DR) in dilute polymer s olutions in terms of solvation of macromolecular chains and formation of re latively stable domains. The domains partly suppress the vortex formation, act as energy sinks, and also play a role in mechanical degradation in flow (MDF). We report ultrasonically determined solvation numbers for a series of copolymers with the same chemical structure but differing widely in thei r intrinsic viscosities. The solvation numbers confirm the model. Thus, we have a criterion for selection of DR agents with low MDF for: oil well oper ations; crude oil transport, fire fighting; high sewer throughput; irrigati on; hydrotransport of solids; marine applications; and biomedical applicati ons including the arteriosclerosis prevention.