In this article we will discus about the measurement of
flow. We will learn that how to measurement of flow .
Measurement of Flow
Flow has been an important parameter for measurement in
industry and also in the biomedical applications such as blood flow
measurement. Fluid can be of different types, like it may be clear or opaque,
clean or dirty, wet or dry, erosive or corrosive. The stream of fluid may be
multiphase vapor, liquid or slurry, also the fluid may have turbulent or
laminar flow, so , different measurement techniques has to be adopted for
different types of fluid flows.
1. Laminar Flow
It is a type of measurement of flow
When the fluid is flowing through the conduit at very low
velocities, the motion of the individual particles are usually along the lines
which are parallel to the conduit walls. The velocity of the fluid profile thus
obtained is greatest at the centre of the conduit and decreases outwards ( near
the wall). This smooth flow of fluid layers one over the above is termed as the
laminar flow.
2. Turbulent Flow
It is also a type of measurement of flow.
When the Flow velocity of the fluid is increased more than
the critical velocity, then the fluid profile no longer remain linear but show
a random motion which is called as the turbulent flow.
3. Variable Head flow meter
These types of meters are the obstruction type meters as
they are placed in between the path of the fluid and hence, puts restriction in
the passage of fluid. A differential pressure or head is created across the
restriction and this differential pressure is a measure of the fluid flow. The
commonly used obstruction meters are the ventury, the flow nozzle and the
orifice.
4. Venturimeter
It is a mechanical device which used to measurement of flow.
The Venturimeter is a device which is used for the
measurement of discharge through a pipe. It is a short pipe that first tapers
to a small cross-section known as throat. The diameter is then again gradually
increased to its original size,as shown in figure.
Advantages of Venturimeter
1. They have low head loss about 10% of the differential
pressure head.
2. They have a high coefficient of discharge ( 0.95 to 0.97)
on account of low loss. Hence they can be used to measure high flow rates in
the pipes having diameter of the order of few meters.
Disadvantages of Venturimeter
1. They have large size which renders them unsuitable for application,
where space is less.
2. Their cost is high due to their large size, also the cost
of installation is high.
Hence it is the measurement of flow if you will find any incorrect
above please comment below in comment box.
For knowing more about the measurement of flow you must
watch this video.