Reviews on drag reducing polymers

Abstract

Polymers are effective drag reducers owing to their ability to suppress the formation of turbulent eddies at low concentrations. Existing drag reduction methods can be generally classified into additive and non-additive techniques. The polymer additive based method is categorized under additive techniques. Other drag reducing additives are fibers and surfactants. Non-additive techniques are associated with the applications of different types of surfaces: riblets, dimples, oscillating walls, compliant surfaces and microbubbles. This review focuses on experimental and computational fluid dynamics (CFD) modeling studies on polymer-induced drag reduction in turbulent regimes. Other drag reduction methods are briefly addressed and compared to polymer-induced drag reduction. This paper also reports on the effects of polymer additives on the heat transfer performances in laminar regime. Knowledge gaps and potential research areas are identified. It is envisaged that polymer additives may be a promising solution in addressing the current limitations of nanofluid heat transfer applications.

Using water‐miscible nonionic hydrophobic monomer associating HPAM as drag reducing agent

“…To date, a variety of DR mechanisms focusing on viscoelasticity, whirlpool stretching, nonisotropic properties, molecular stretching of polymers, and laminarization of turbulent flow have been mainly discussed along with the behaviors of polymeric additives in turbulent flow. Nevertheless, there are still no universal accepted models and the mechanism of drag reduction by polymers remains elusive . In practical researches and field applications, DR performance is the most important indicator that should be taken into consideration.…”