EXPERIMENT NO: 1
1) OBJECTIVE:
To measure the extend of the reduction in flow and
contraction of the stream as water discharged form a sharp edged orifice.
2) APPARATUS REQUIRED:
a) Collection tank
b) Tube manometer
c) Micrometer
d) Discharge tank
e) Glass tank with overflow
f) Water pump
g) Stop watch
h) Adjustable valve
3) THEORY:
The orifice consists of a flat plate with a hole drilled in it. When a fluid
passesthrough an orifice, the discharge is often considerably less than then the amo
untcalculated on the assumption that the energy is conserved and that the flow
throughthe orifice is uniform and parallel. This reduction in flow is normally due t
o acontraction of the stream which take place through the restriction and continues
for some distance downstream of it.
Knowledge of the flow through an orifice and orifice size can be used indeterminin
g the sizing and selection of a vacuum pump or system. Many of thesituations enco
untered when sizing vacuum equipment, particularly in materialhandling type appli
cations are resolved with a basic understanding of how flow through an orifice
works.
In determining the performance of water flow through an orifice, the coefficient of
discharges, Cd, the coefficient of contraction, Cc and coefficient of velocity, Cv
are needed. These three coefficients allow us to understand the effect of friction on
water flow clearly. Each of these coefficient is a ratio of the actual performance to
ideal performance as related to discharge, velocity and contraction.
4) PROCEDURE:
a. The pipes were all ensure to be properly connected. The water was allowed
to flow through the pump into the tank.
b. The inflow of water was regulated when when the water level reached the
heightof the overflow pipe so that a small steady discharge was obtained fro
m the overflow.
c. the values of Ho and Hc were recorded.
d. The diameter of the water flow through the orifice was recorded
by calculating the difference in reading using a micrometer.
e. The inflow of the tank was then reduced to lower the level in the tank in
stages.
f. The discharge from the orifice for other three different stages.
g. Steps 2 to 5 were repeated with different discharge rate.
h. The data obtained were all recorded.
5) RESULT:
Time(s) Volume Discharge Diameter Ho (mm) Hc (mm)
discharged (m3/s) (mm)
(m3)
Area of Ideal Actual Theoretical Coefficient Coefficient Coefficient
orifice velocity, velocity discharge of velocity of discharge of
(m2) Vo (m/s) Vc (m/s) Qo (m3/s) Cv contraction
7) CONCLUSION:
In this experiment, we have successfully calculated the coefficient of discharges,
Cd, the coefficient of contraction, Cc and coefficient of velocity, Cv. we can
conclude that the Ho is proportional to Q. Thus, when Ho increase, Q will also
increase. Besides, from the result calculated we also can conclude that the increase
in the diameter of orifice will increase the Volume of fluid discharge as pressure
acting on it increased.
