Turbulent Drag Reduction by Polymers, Surfactants and Their Mixtures in Pipeline Flow (original) (raw)
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Drag reduction in turbulent pipeline flow of mixed nonionic polymer and cationic surfactant systems
The Canadian Journal of Chemical Engineering, 2013
Turbulent drag reduction behaviour of a mixed nonionic polymer/cationic surfactant system was studied in a pipeline flow loop to explore the synergistic effects of polymeric and surfactant drag reducing additives. The nonionic polymer used was polyethylene oxide (PEO) at three different concentrations (500, 1000, and 2000 ppm). The surfactant used was cationic octadecyltrimethylammonium chloride (OTAC) at concentration levels of 1000 and 2500 ppm. Sodium salicylate (NaSal) was used as a counter-ion for the surfactant at a molar ratio of 2 (MR = Salt/OTAC = 2). Relative viscosity and surface tension were measured for different combinations of PEO and OTAC. While the relative viscosities demonstrated a week interaction between the polymer and the surfactant, the surface tension measurements exhibited negligible interaction. The pipeline results show a considerable synergistic effect, that is, the mixed polymer-surfactant system gives a significantly higher drag reduction (lower friction factors) as compared with pure polymer or pure surfactant. The addition of surfactant to the polymer always enhances drag reduction. However, the synergistic effect in mixed system is stronger at low polymer concentrations and high surfactant concentrations.
Experimental Study on Drag Reduction by Surfactant Additives in Turbulent Pipe Flow
Strömungssimulation im Wasserbau (Flow Simulation in Hydraulic Engineering), 2006
Schleppspannungsverminderung wurden für verschiedene Temperaturen und Rohrdurchmesser durchgeführt. Zeitgleich wurden Messungen zur räumlichen Geschwindigkeitsverteilung an der Tensidströmung mit der Hilfe eines PIV-Systems (particle image velocimetry) durchgeführt.
Complex Behavior of Polymers as Drag Reducing Agents Through Pipe Fittings
Journal of Applied Fluid Mechanics
Polymer induced turbulent drag reduction has significant industrial importance and finds application in industries, oil and gas, fire-fighting, marine, irrigation, biomedical etc. Most of the reported literature is focused on the skin drag reduction in pipe flow employing drag reducing additives (DRAs) like polymers, surfactants, fibres and suspensions. In this work, the effect of polymeric addition on the total drag reduction (skin and form) is studied for turbulent flow of water through various fittings like 45 degree elbow, 90 degree miter, sudden expansion and sudden contraction. Different polymers like PAM, PEO, HPMC have been employed as DRAs at various concentrations and pressure drops. The results indicate a complex and interesting behavior. When compared to the results reported for pipe flow, even in this case polymers are found to give total drag reduction (TDR) though less relative to skin drag alone. The extent of TDR is found to depend on the nature of fitting, polymer and its concentration and the pressure drop used. From the results, it is also clear that there is a strong need to further investigate the problem using sophisticated analytical tools on rheometry and polymer degradation.
Brazilian Journal of Chemical Engineering, 2016
- The main aim of this paper is to present a possibility to enhance the drag reduction effect in straight pipe flow by the simultaneous addition to the transported liquid of a small amount of high molecular weight polymers and surfactants. Qualitative analysis of the polymer-micellar additive influence on the shape and character of flow resistance curves has been performed. Also multicomponent polymer-micellar solution flow resistance curves were compared with appropriate single additive polymer or surfactant solution flow resistance curves. The experimental data shows that, for polymer-micellar solutions, the stable transitional zone between the laminar and the turbulent flow regions is extended toward higher values of the critical Reynolds numbers. Occurrence of the phenomenon can be explained by the flow laminarization caused by polymer-micellar aggregates. Existence of the third extended drag reduction zone in the turbulent range of flow has also been observed for the first time.
Novel polymer-surfactant complex for enhancing the flow in pipes
A special unresolved issue in liquid transportation is the high energy consumption attributed to the turbulent mode of their transportation, despite many efforts that have been made to solve this problem, such as adding minute concentrations of polymers, surfactants or the complex mixtures of these materials. A universally acceptable solution to this has not been proffered, in view of this; the present work introduces a novel complex mixture system to enhance the drag reduction efficiency of polymeric drag with the use of a polymer, polyacrylamide (PAM) and surfactant, (Triton X-45). Both materials were individually and their complex mixtures tested in a Brookfield viscometer and Rotating Disk apparatus (RDA) at varied concentrations and rotational speeds (r.p.m), investigations on their drag reduction mechanisms was as well undertaken. The complex mixtures of these materials at 1500ppm concentration were able to reduce drag by 54% unlike their individual studies which gives 33% and 35% respectively. It was also observed that the time taken for mechanical degradation increased with less degradation and display drag reduction for a larger range of Reynolds numbers which later realigned which could be attributed to the critical role played by the complex mixtures which is greatly dependent upon the alky chain in the surfactant.
Turbulent drag reduction by additives
2013
Drag reduction involves many subjects of interest such as polymer science, fluid mechanics and applied mathematics. The use of additives to enhance flow in petroleum pipelines has received the greatest attention due to a significant commercial success. In this study, we study the effect of the addition of the most common drag reducing agents (polymers and surfactants) on the characteristics of turbulent flows.
Drag reduction induced by polymer in turbulent pipe flows
Chemical Engineering Science, 2013
Equations of the velocity distribution and friction factor in turbulent drag reducing flows are derived. The approach of predicting the onset Reynolds number for drag reduction has been provided. The approach of determining the optimal polymer concentration for the Maximum Drag Reduction is obtained.
Drag Reduction with Polymer Mixtures in Pipes of Different Diameters
Arid Zone Journal of Engineering, Technology and Environment, 2019
Transporting crude oil and other fluid in pipelines of different sizes over long distances in process industries require high amount of energy which results to high cost of installing pumping stations and maintenance. Addition in part per million (ppm) of high molecular weight polymeric solution reduce such cost. The effect of pipe diameter, oil input volume fraction and flow rate (superficial velocity) on drag reduction (DR) in horizontal oil-waterflows was investigated in unplasticised polyvinylchloride (uPVC) horizontal pipe with two different pipe diameters (0.012 and 0.02 m IDs). The two liquids used were diesel oil (ρ = 832 kg/m3, µ = 1.66 cP) and water (ρ = 1,000 kg/m3, µ = 0.89 cP) as test fluids at ambient conditions (25°C, 1 atm). Partially hydrolyzed polyacrylamide (HPAM; magnafloc 1011), polyethylene oxide (PEO) and Aloe Vera Mucilage (AVM) separately, as well as mixture of HPAM-AVM and PEO-AVM at different oil input volume fraction (δo; 0,0.25, 0.5, 0.75 and 1) and flow...
Turbulent drag reduction by surfactants
Europhysics Letters (EPL), 2006
Yz -Drag reduction. PACS. 82.70.Uv -Surfactants, micellar solutions, vesicles, lamellae, amphiphilic systems (hydrophilic and hydrophobic interactions). PACS. 83.50.Rp -Wall slip and apparent slip.