Review of mechanical degradation and de-aggregation of drag reducing polymers in turbulent flows

Polymer scission in turbulent flows

“…However, in a turbulent flow, polymers are subject to mechanical degradation due to the fluctuating strain rate, which stretches polymers and thus causes their scission. Since turbulent drag reduction decreases with the molecular weight of the dissolved polymers (Virk 1975), the efficacy of polymers as drag reducing agents diminishes in time, with a strong impact on both industrial applications and laboratory experiments (Paterson & Abernathy (1970), Moussa, Tiu & Sridhar (1993), den Toonder et al (1995, Choi et al (2002), Vanapalli, Islam & Solomon (2005), Vanapalli, Ceccio & Solomon (2006), Elbing et al (2009), Pereira & Soares (2012), Owolabi, Dennis & Poole (2017), see also the editorial of Poole (2020) and the review of Soares (2020)).…”

“…(2002), Vanapalli, Islam & Solomon (2005), Vanapalli, Ceccio & Solomon (2006), Elbing et al. (2009), Pereira & Soares (2012), Owolabi, Dennis & Poole (2017), see also the editorial of Poole (2020) and the review of Soares (2020)).…”

“…Unlike the fragmentation of liquid jets, sheets, or drops (Villermaux 2007, 2020), the modelling of flow-driven scission in turbulent polymer solutions is still in its infancy (Soares 2020). The reason for this has to be sought in the difficulty of including the microscopic details of the scission process in constitutive models of polymer solutions.…”

Thriving artificial underwater drag-reduction materials inspired from aquatic animals: progresses and challenges

“…The addition of the polymer inhibits the uid's radial pulsation and reduces the energy consumption. 169,198,199 The surface of the hierarchical comb-shaped hydrophilic polymer brush (HCHPB) design based on sh mucus was proposed by Su et al 152 The surface has nanostructures that have not only good lubricating properties and drag reduction properties but also have good anti-biological adhesion properties, which provide new ideas for self-cleaning and preventing microbial adhesion.…”

Mass Transfer Behavior of a Rotating Hexagonal Cylinder Reactor Suitable for Water Pollution Control

“…The speed of mass transfer was quantified by the electrochemical method which implicates determining the limiting current of the K 3 Fe(CN) 6 reduction at the cathode in a bulky excess of NaOH as an auxiliary electrolyte 13. As drag‐decreasing polymers are employed in practice to diminish mechanical power consumption under turbulent stream situations as a result of damping the small size energy dissipating vortices by the polymer molecules 14–18, it would be of interest from the economic point of view to consider the influence of a drag‐decreasing polymer on the speed of mass transfer and hence the productivity of the rotating cylinder reactor in performing diffusion‐controlled reactions.…”