Oil and Gas Refining Engineering Department
Differential Flow Meter Orifice and Venture
Fluid Flow Laboratory
Second Year
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: االسماء
حسين صادق عبد الرضا -1
زين العابدين صبار حمود -2
: اشراف
االستاذ حمزة عبد االمير
AIM: To determine the co-efficient of
discharge of the orifice meter
: THEORY
An orifice plate is a device used for
measuring the volumetric flow rate. It uses
the same principle as a Venturi nozzle,
namely Bernoulli's principle which states
that there is a relationship between the
pressure of the fluid and the velocity of the
fluid. When the velocity increases, the
pressure decreases and vice versa. An
orifice plate is a thin plate with a hole in
the middle. It is usually placed in a pipe in
which fluid flows. When the fluid reaches
the orifice plate, with the hole in the
middle, the fluid is forced to converge to
go through the small hole; the point of
maximum convergence actually occurs
shortly downstream of the physical orifice,
at the so-called vena contracta point. As it
does so, the velocity and the pressure
changes. Beyond the vena contracta, the
fluid expands and the velocity and pressure
change once again. By measuring the
difference in fluid pressure between the
normal pipe section and at the vena
contracta, the volumetric and mass flow
rates can be obtained from Bernoulli's
equation. Orifice plates are most
commonly used for continuous
measurement of fluid flow in pipes. This
experiment is process of calibration of the
given orifice meter
:PROCEDURE
Switch on the power supply to the pump
Adjust the delivery flow control valve and note
down manometer heads (h1, h2) and time taken
for collecting 10 cm rise of water in collecting
tank (t). (i.e. Initially the delivery side flow
control valve to be kept fully open and then
gradually closing) Repeat it for different flow
rates Switch off the pump after completely
..opening the delivery valve[1]
: Calculate
: CONCLUSIONS
As the flow expands, the pressure increases
because the volume decreases. There is a loss of
velocity in the expansion of the flush that
increases the pressure. We noticed that as the
spindle height increases, the actual flow rate also
increases. There is a linear relationship between
the two. We expected to see an exponential
increase in flow as the difference in pressure
increased. This is because Bernoulli's equation
states that the pressure drop is equal to the
square of the velocity. Our results were as
expected for the discharge coefficient of both
meters. The Fenori CD is expected to be larger
than the aperture slot. This is because the Venturi
meter has a gradual change in the diameter of
the tube while the aperture plate contains a
sudden and radical change in the diameter where
the liquid flows. The dump factor could not be
greater than 1. However, some of our results
were more than 1. This may be due to a human
error in data recording. For future laboratories, I
suggest more than one person take the readings
and then we can check again to ensure correct
registration[2]
Discussion : { Hussein Sadiq Abdulrdaa }
What is the difference between Orifice and
?Venture
A Venture meter can be used to measure the flow
rates of all incompressible fluids (gases with low
pressure variations , as wells as liquids) , where
as an Orifice meter is generally used for
measuring the flow rate of liquid . … the flow
.continues through the pipe line
?What is the purpose of a Venture
A Venture meter is a system for speeding the
flow of the fluid by constricting it in a cone shape
tube . In the restriction the fluid must increase its
velocity reducing its pressure and producing a
partial vacuum . As the fluid leave the
constriction , its pressure increase back to the
. ambient or pipe level
? What is the purpose of Orifice
An Orifice plate is a device used measuring flow
rate , for reducing pressure or for restricting flow
( in the latter two cases it is often called a
restriction plate ). Either a volumetric or mass
flow rate may be determained , depending on on
.the calculation associated with Orifice plate
? What are the applications of Orifice meter
It is used to measure the flow rate of fluids in
their single state (gaseous state or liquid state ) it
can also be used to measure the flow rate of
fluids in a mixed state ( both gaseous and liquid
states ) such as , wet steam , or natural gas with
.water
Discussion : { Zain Al Abidine Sabar Hamoud }
? What happens in a venture
The venture effect is the reduction in fluid
pressure that results when a fluid flows through a
constricted section ( or choke ) of a pipe . The
venture effect is named after its discoverer ,
. Giovanni battista venture
? Does an orifice reduce pressure
An orifice affects flow rate ( volume ) down and
pressure up as it decreases in diameter . Vice
versa , it increases volume while dropping in
. pressure
? What is the disadvantages of venture tube
Disadvantage of venture meter : They are large in
size and therefore , where space is limited , they
can not be used . initial costs installation and
expensive maintenance. … Maintenance is not
easy . It can not be modified to measure the
.pressure beyond a maximam speed
: Sources
www.srm-aero.weebly.com ]1[
Essays, UK. (November 2018). Laboratory ]2[
Experiment on Venturi Meter and Orifice Meter.
Retrieved from
https://www.ukessays.com/essays/physics/labor
atory-experiment-on-venturi-meter-and-orifice-
meter.php?vref=1
