Effect of solvent on polymer degradation in turbulent flow

Scission-induced bounds on maximum polymer drag reduction in turbulent flow

“…[20][21][22] Molecular weight, polymer concentration, solvent quality, turbulent intensity, and flow geometry have been identified as important factors influencing polymer degradation in turbulent pipe flows. [7][8][9][10][11]23 In particular, it has been reported that high molar mass polymers break preferentially relative to low molar mass chains 8,9,11 and that scission occurs predominantly at the chain midpoint. 24 In addition, it has been found that the degree of degradation is correlated with the turbulent intensity of the flow.…”

“…In some cases the molar mass distributions of degraded polymers have been measured using gel permeation chromatography with refractive index detection and calibration with standards of known molar mass. 7,9,10,23 Because of the development of light-scattering detectors, absolute characterization of polymer molar mass distribution by gel permeation chromatography is today possible. [26][27][28][29] Here we apply this technique to measure the absolute molar mass distribution of polymer molecules that have been subjected to turbulent flow.…”

Mechanical degradation of polysaccharide guar gum under turbulent flow

“…Even though the GGV shows its shear-stable DR behavior as time passes, the initial drop of %DR clearly appeared. Such mechanical degradation of the polymers under turbulent flow, in general, is known to be qualitatively related to various factors such as molecular structure, temperature, polymer-solvent interaction, polymer molecular weight and its distribution, and turbulent intensity [12,13,20]. Recently we reported the mid-scission of the DNA chains under turbulent flow and confirmed its degradation mechanism using an electrophoresis method [16].…”

“…Consequently, major decreases in the drag reduction effectiveness will result [8] and the drag reduction with polymeric additives has been limited to short-term industrial applications. Therefore, resolving the degradation problem is a key issue in taking advantage of not only this technology but also other related areas [11] and there have been many investigations, which focus on understanding the origin of this degradation [12,13].…”

Turbulent Drag Reduction with Polymers in Rotating Disk Flow

“…Up to now, to analyze turbulent DR, most research groups have adopted the pipe flow [38][39][40][41], which produces a pressure-driven flow in an enclosed channel as an internal flow. In contrast, a high-precision rotating disk apparatus system [42] has been used for measuring DR in an external flow as a function of time.…”