Experimental Investigation Coefficient of Discharge (Cd) for Venturimeter

Abstract

Flow is the volume of fluid that passes in a
unit of time; it is also called discharge or rate
of flow. It is generally expressed in m3
/s for a
large quantity of flow rate, it is expressed in
lit/s. Measurement of discharge is the major
process in many industrial applications. Some
applications have discharge through open
channels, whereas some applications have
discharge through a closed pipe. A
venturimeter is a device that is used to
measure the rate of flow of fluid through a
pipe or closed conduit. It is based on the
Principle of Bernoulli’s Equation, which
states that by reducing the cross-sectional
area of the flow passage, the pressure
difference will give the quantity of liquid
flowing through the pipe. Venturimeters can
be used for both compressible and
incompressible fluids. It can be used with low
heads and with excellent accuracy.
Venturimeter is expensive and faces some
difficulties in maintenance. The coefficient of
discharge (Cd) is an indication of the
accuracy of the flow measuring devices. The
value of Cd is equal to one indicates the
Actual Discharge and Theoretical Discharge
are the same, but in actual practice due to
losses, the actual discharge is always less than
the Theoretical Discharge. The average
discharge coefficient of a Venturimeter is
found to be 0.90.