Browsing by Author "Asmelash Getachew"

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    Determination of Viscosity of Oil by Falling-Sphere Method using Digital-Imaging system
    (Addis Ababa University, 2009-06) Asmelash Getachew; Asfaw Araya (PhD)
    Viscosity is the most important physical property for lubricating oils. The measurement of viscosity resists on the velocity limit measurement of falling-ball, corrected principal identified effects (edge or wall effects, inertial effects, and end effects). In this research falling-sphere technique is used to measure the viscosity of Total quartz 20W50 motor oil by monitoring the terminal velocity at which a sphere falls under gravity in a cylindrical tube containing the test fluid. The experiments, the sphere is monitored using video system and the position coordinate and time are measured. The principal difficulties with this system are the measurement of the velocity of the ball. The result of the experiment agree with the theoretical values and reported value by Total oil company, even-though, there are uncertainties in measurement of falling velocity, corrected terminal velocity, density of sphere, and fluid and radius