Experimental Study of Friction Factor Reduction by Adding Aloe Vera Gel in Pipes Transporting Dams Sediments

Abstract

The phenomenon of siltation represents an enormous risk for the lifespan and safety of dams, and there are several methods for evacuating sediments, of which the hydraulic dredging technique is the most widely used. But during this operation there are load loss exists so it is necessary to find solutions to reduce it. The purpose of this work is to use the Aloe Vera gel as a load loss reducer during hydraulic dredging of dams. To carry out this study, a rheumatic characterization of dams sediments and dams sediments - Aloe Vera gel mixtures was carried out using a torque controlled rheometer (Discovery Hybrid Rheometer DHR2 from TA instrument) and a hydraulic study carried out on a closed-circuit installation comprising three pipes of different diameters and lengths, supplied by a centrifugal pump driven by a variable speed Diesel engine. The experimental work was carried in pipe of diameter D1=36.16 mm and length L1 = 12.24 m with the quantity of Aloe Vera 2 to 10 wt% and different speed of rotation of pump. The flow curves as a function of dose of Aloe Vera added to dam sediments were analysed by the Casson model. The calibration of installation has been fitted by the Blasius equation. The addition of Aloe Vera gel with a quantity range between 2 and 10 wt% to dams sediments of 40 wt% and 45 wt% induces an decrease in the yield stress and the viscosity infinite of dams sediments. The study also demonstrated that adding of 6 wt% of sodium tripolyphosphate to 40 wt% and 45 wt% dam sediments decreased the friction factor by 75% and 85% respectively