Investigation of the drag reduction of hydrolyzed polyacrylamide–xanthan gum composite solution in turbulent flow

Abstract

In this paper, the rheological properties, drag reduction properties, and flow field characteristics of hydrolyzed polyacrylamide (HPAM) solution, xanthan gum (XG) solution, and HPAM–XG composite solution were analyzed to explore the synergistic effect of flexible and rigid polymer. The experimental results show that the viscoelasticity and shear thinning of the composite solution are significantly enhanced compared with single‐component solution, which indicates that the rigid XG has an effect on the viscoelasticity of the flexible HPAM solution. Compared with the single‐component solution, the drag reduction rate of HPAM–XG composite solution is higher, and the mean flow field of HPAM–XG composite solution changes less after being sheared for 300 minutes, which means that not only the drag reduction effect of composite solution is better, but also the shear resistance. Compared with single‐component solution, the mean velocity distribution of the composite solution moves upwards most obviously in the logarithmic layer, the peak of velocity fluctuation in the main flow direction of composite solution is higher, the suppression degree of normal velocity fluctuation is deepened, and the corresponding vorticity intensity is also reduced. These changes in the flow field characteristics explain the reason for the drag reduction gain of the composite solution.

Drag Reduction by Polymer Additives: State-of-the-Art Advancements in Experimental and Numerical Approaches

“…Under aqueous conditions, the polymer chains stretch due to favorable solvent–polymer interaction, leading to the developing elastic retractive force in the polymer network that balances the reduction in the entropy associated with the resistance of the polymer to the swelling-induced polymer network. , The degree of macro or micro scale swelling is impacted by the PAM dissolution conditions, such as temperature, pH, and the coexistence of metallic ions. , In fact, the presence of mono and bimetallic ions allows the presence of incomplete swelling due to the electrostatic interactions between the exposed carboxylate groups with alkali and alkaline earth metal, forming aggregates, negatively impacting the polymeric linearity, and reducing their tendency for hydration. To overcome the salinity issue, polymeric structural modifications were usually performed by adding some surfactants or copolymers, such as PEO or XG, to the HPAM backbone to alter the net charge of the existing molecules. ,,,− Recently, our research group has investigated the performance of virgin polymers of HPAM, XG, PEO, and mixtures of HPAM with XG and PEO at different salinity levels mimicking industrial conditions by using an industrial-scale fluid flow loop and a rotational rheometer. The effect of salinity levels on DR performance and degradation rates of virgin and mixture of polymers were studied and discussed.…”

Effect of Salinity on Drag Reduction of Additives and Mixtures under Turbulent Flow

“…In another study conducted by Li et al, mixtures of HPAM and XG in water have been tested at concentrations ranging between 50 and 500 ppm, but at high values of Re , reaching up to 140 000. In their study, they highlighted the role of mixtures in improving the shear-resistant behavior compared with HPAM alone.…”

“…To avoid such challenging issues associated with working under saline conditions, several reported works – suggested performing some polymeric structural modifications through introducing some surfactants or copolymers into the HPAM backbone to alter the net charge of the existing molecules. Generating such systems, through mixtures of polymer additives, will make up a tolerant friction reducer that is able to work under diverse saline conditions. ,– For instance, Mohammadtabar et al performed a comparative study on virgin polymers of HPAM, poly­(ethylene oxide) (PEO), and xanthan gum (XG) under turbulent flow conditions ( Re = 20 600) using a fluid flow loop. The maximum DR and degradation behavior have been assessed in distilled water .…”

Aligned cellulose nanocrystal composite filament with high tensile strength enhanced by cationic polyacrylamide via flow focusing approach

“…As a versatile water-soluble polymer, polyacrylamide (PAM) has high chemical activity and is often used as a reinforcing agent in the paper industry (Li et al 2022;Muterko 2022). The cationic polyacrylamide (CPAM) prepared by the Hoffmann reaction can have a relatively small molecular weight, such that it does not easily flocculate the CNCs dispersions.…”