Degradation effects of dilute polymer solutions on turbulent drag reduction in pipe flows

Visco-elastic flow past circular cylinders mounted in a channel: experimental measurements of velocity and drag

“…The polymer is a partially hydrolysed polyacrylamide (PAMH) called Superfloc A-110 from Cytec Industries, which has a molecular weight of 4-6 × 10 6 g/mol. This polymer consists of long chains of monomeres and it was found to show little mechanical degradation during the experiments in agreement with the results of [15]. The highly viscous solution combined with the long chained polymers leads to a strongly elastic solution without shear thinning, also known as a Boger fluid.…”

Drag reduction by polymer additives in a turbulent pipe flow: numerical and laboratory experiments

“…The pump used is a so-called disk pump, manufactured by Begemann. This type of pump avoids strong degradation of the polymers (den Toonder et al 1995a). Before entering the pipe, the fluid passes first through a flow straightening device and then through the settling chamber, which contains another flow straightening device as well as several screens.…”

“…The advantage of this polymer over other types of polymer encountered in the literature (e.g. Polyox WSR301, Union Carbide, or Separan AP273, Dow Chemical Company), is that it is relatively resistant to mechanical degradation (see den Toonder et al 1995a). Mechanical degradation is the breaking of the polymers by mechanical action, which reduces their molecular weight and thus their capability for drag-reduction (see Virk 1975).…”

Turbulent drag reduction by polymer additives in parallel-shear flows

“…This phenomenon, discovered by Toms (1948), has prompted a large number of studies to better understand the underlying mechanism, with researchers approaching the problem from theoretical, experimental and numerical perspectives. Periodic overviews of the literature published on the subject can be found in the reviews by Virk (1975), Den Toonder et al (1995, Graham (2004), Procaccia, Lvov & Benzi (2008) and White & Mungal (2008) among others.…”