[PDF] Investigating The Effect Of Polymer Molecular Weight On Drag Reduction Performance Using Rotating Disk Apparatus Rda eBook

Author : Nurul Fatimah Abdul Basir
Publisher :
Page : 112 pages
File Size : 15,40 MB
Release : 2013
Category : Pipelines
ISBN :

GET BOOK

The investigation of turbulent drag reduction, which is caused by the addition of a small amount of polymer or some other substances to the liquids flowing systems has been the focus of attention of many scientists for the last decades. Due to the reduction of the drag, pumping power for the pipeline will significantly reduced and thus will decrease the cost of electricity in total production cost. In this study, the effect of the presence of a drag reducing agent (DRA) and its variety of molecular weight on the torque produced in rotating disk apparatus containing water is investigated. The experimental procedure was divided into three parts; obtaining several different polymer molecular weights using ultrasonication method, testing the water using different polymer molecular weight at different polymer concentration and lastly is adding the different concentration of surfactant in the fixed concentration of water- polymer solution. Three polymer molecular weights are obtained by using ultrasonificator method with value of 11.7967 x106 g/mol, 4.830 x106 g/mol and 1.7179 x106 g/mol. A drastic reduction of drag in the turbulent flow of solutions as evaluated with torque differences in comparison to the pure solvent can be observed, even when only minute amounts of the additives are added. The percentage of drag reduction is relatively increases as we increase the polymer molecular weight and polymer concentration. A maximum drag reduction of 47.62% has been observed at polymer molecular weight of 11. 7697 x106 with polymer concentration of 200 ppm. In polymer- surfactant complex solution, 29% of drag reduction were reported with surfactant concentration of 2000ppm.

Author : Gin Chain Liaw
Publisher :
Page : 318 pages
File Size : 14,14 MB
Release : 1968
Category : Drags (Hydrography)
ISBN :

GET BOOK

"The effects of polymer chain flexibility, molecular weight and entanglement capacity, and of polymer solution concentration on drag reduction in nonpolar solvents were studied in this investigation. Three samples of polydimethyl siloxane in toluene, five samples of polyethylene oxide in benzene, two samples of cis-polyisoprene in toluene, trans-polyisoprene in toluene, cis-polybutadiene in toluene, ethyl cellulose in toluene and a copolymer of epichlorohydrin and polyethylene oxide in toluene were studied. Molecular weights of all polymers were estimated from intrinsic viscosity, except for the molecular weight of the copolymer which was given by the manufacturer. Turbulent and laminar flow pressure drop data were obtained in four capillary tubes (0.107, 0.0642, 0.0328 and 0.0104 inch ID) for all the polymer-solvent systems. Turbulent flow pressure drop data for some of the above polymer-solvent systems were also obtained in the pipe flow unit (2.0, 1.0 and 0.51 inch ID). For a given tube, at lower concentrations the normal transition region appeared between laminar and turbulent regions; as the concentration increased, the transition tended to disappear. At constant solution concentration, the transition region tended to disappear as the tube diameter decreased ... Correlations were obtained for estimating the amount of drag reduction for "dilute" and "concentration" solutions. Both correlations were tested with the polymer-solvent systems studied in this investigation and with data obtained from literature ... The effect of degradation on drag reduction was more noticeable at lower concentrations than at higher concentrations. This suggests that the absolute rate of molecular degradation may have been approximately the same for all concentrations of any polymer whose wall shear stresses (or shear rates) were of the same magnitude at any given flow rate. In the dilute solutions a significant number of the effective molecules were degraded while in the more concentrated solutions, the same amount of degradation had a much smaller effect on the drag reducing capacity of the solutions"--Abstract, leaves i-iii.

Author : R. R. Walters
Publisher :
Page : 66 pages
File Size : 39,14 MB
Release : 1974
Category : Diffusion in hydrology
ISBN :

GET BOOK

The effect of polymer molecular weight on turbulent diffusion and drag-reduction was investigated over a uniformly distributed polymer injection area. The purpose of the experiments, carried out in a porous wall pipe flow facility, was to determine optimum values of polymer molecular weight and injection mass flux for attaining maximum skin-friction reduction over a distributed injection area and to investigate associated turbulent diffusion characteristics. It was found for this type of polymer supply system, which provided polymer directly to the required wall shear stress region, that the optimum molecular weight was approximately an order of magnitude less than that normally used in skin-friction reduction applications with homogeneous solutions and localized injection ...Abstract, p. iii.

Author : Paul Peyser
Publisher :
Page : 20 pages
File Size : 14,92 MB
Release : 1971
Category :
ISBN :

GET BOOK

The frictional drag reduction of high-molecular-weight polyethylene oxide and polystyrene solutions under turbulent flow conditions was studied as a function of temperature, solvent power, and solvent viscosity. A rotating disk apparatus was used to make the drag reduction measurements. For aqueous polyethylene oxide solutions, at concentrations well above that needed to produce maximum drag reduction, all drag reduction data reduced to a common curve when percent drag reduction was plotted against the Reynolds number for the flow. However, for polyethylene oxide solutions below this optimum concentration the drag reduction-versus-Reynolds number curves showed decreasing drag reduction with increasing temperature. The data are explained primarily in terms of the inverse temperature solubility characteristics of polyethylene oxide in water. The percent drag reduction of polystyrene in nonaqueous liquids was found to be greater in good solvents than in poor ones. It was also found that increases in solvent viscosity and decreases in temperature increased the percent drag reduction. The results are discussed in relation to the current drag reduction theories and are shown to be in opposition to Virk's theory. It is concluded from the data that drag reduction is very likely a function of a relaxation time phenomenon involving the polymer molecules and the flow system. The results also emphasize the importance of considering solvent power, viscosity, and temperature in the design of an efficient drag reduction system. (Author).

Author :
Publisher :
Page : 121 pages
File Size : 30,83 MB
Release : 1966
Category :
ISBN :

GET BOOK

Tube flow data indicate that the drag reduction of high molecular weight polymer solutions decreases in an orderly fashion with inc.eased molecular coiling of the polymer. A correlating equation for this effect is presented. For three polymers at four concentrations the maximum drag reduction was obtained at temperatures less than 105F and at 140F solutions of all three polymers suffered a decrease in drag reduction. A graphical relationship is presented that qualitatively correlates the variation of viscosity and drag reduction caused by a variation in temperature. A decrease in drag reduction occurs if low concentration of high molecular weight polymers are subjected to steady state turbulent tube flow. A slow decrease in viscosity of high molecular weight solutions due to physical adsorption on the solid surfaces in glassware as well as chemical degradation during static storage can be mitigated by adding isopropanol or using deionized water. The average molecular weight of different samples of the same polymer can vary by as much as 50 percent. (Author).

Author : Gail T. Pruitt
Publisher :
Page : 125 pages
File Size : 31,5 MB
Release : 1965
Category :
ISBN :

GET BOOK

Tube flow data on some 16 polymers indicate that drag reduction is a function of molecular contour length, segmental side groups, concentration, pipe diameter and Reynolds number. The maximum drag reduction actually obtained with any drag reducing polymer is approximately 80% of that which would be obtained if completely laminar flow was maintained. A relationship that correlates drag reduction, concentration and molecular dimensions is suggested for a constant Reynolds number and pipe size. It infers that a critical concentration of polymer exists, below which no drag reduction occurs. Also for some given concentrations and pipe size a critical velocity exists below which no drag reduction occurs. Rheological data for two polymer solutions are presented in terms of elastic energy. (Author).

Author :
Publisher :
Page : 0 pages
File Size : 48,19 MB
Release : 2004
Category :
ISBN :

GET BOOK

Experimental studies of polymer drag-reduction were carried out in the laboratory of Thomas J. Hanratty. Companion studies were carried out in the polymer laboratory of Anthony J. McHugh so that the performance of drag-reducing polymer solutions can be related to their rheological and rheo-optical properties in simple non-turbulent flows. The work was influenced by the notion that aggregation of polymer molecules could be an important role. A remarkable finding is that molecular weight and molecular weight distribution need not change as the drag-reducing ability of the polymer solution degraded. Rheo-optical studies in a Couette device showed that effective polymer solutions develop turbidity over a range of shear rates characteristic of those used in the flow loop. This study shows that the drag reduction can be enhanced by using mixing and delivery procedures which enhance the formation aggregates.