To Determine the Discharge coefficient of given orifice meter

Requirements: Hydraulic bench and Orifice Meter Apparatus.

The principle of the orifice meter is identical with that of the venturi meter. The reduction of the cross section of the flowing stream in passing through the orifice increases the velocity head at the expense of the pressure head, and the reduction in pressure between the taps is measured by a manometer. Bernoulli’s equation provides a basis for correlating the increase in velocity head with the decrease in pressure head. One important complication appears in the orifice meter that is not found in the venturi. Because of the sharpness of the orifice, the fluid stream separates from the downstream side of the orifice plate and forms a free-flowing jet in the downstream fluid. A vena contracta forms, as shown in figure.