Drag Reduction of Complex Mixtures in Turbulent Pipe Flows

Abstract

Abstract The drag reduction of high molecular polymer solutions can be divided into two types: Type A and B. Type A corresponds to the solutions of synthetic polymers such as polyethylene oxide or polyacrylic amide. In contrast, Type B corresponds to the solutions of biopolymers such as xanthan gum, guar gum, and polysaccharide. Experiments were performed to measure the friction factor and heat transfer coefficient for the aqueous suspensions of graphene oxide shin-plate particles. The results show that the complex fluids exhibit a Type B drag reduction phenomenon in the turbulent flow range. The onset point of the drag reduction was found to be 𝑅𝑒√𝑓 ≅ 260 for Cw=0.1 wt%. This point increased compared to the experimental results for Cw = 0.5 wt% graphene oxide solutions that have been reported on drag reduction. In general, aqueous suspensions of fine particles are characterized by an increase in the friction factor and the heat transfer coefficient as compared to water. However, the aqueous suspension of the graphene shin-plate particles produces the drag reduction of the friction factor and increases the heat transfer coefficient. Therefore, suspensions become a useful carrier for the cooling pipeline system. Considering the predicted velocity profiles of the aqueous suspensions of graphene oxide shin-plate particles and the dried malted rice culture solutions classified as biopolymer, it was pointed out that the thickness of the viscous sublayer increases, and the width of the buffer zone narrows in the turbulent pipe flow on the mechanism of Type B drag reduction.