The 18th & 19th weeks
1. Pitot Tube:
is a pressure measurement instrument used to
measure fluid flow velocity. The pitot tube was invented by
the French engineer Henri Pitot in the early 18th century[1] and was
modified to its modern form in the mid-19th century by French
scientist Henry Darcy.
It is widely used to determine the airspeed of an aircraft, water speed
of a boat, and to measure liquid, air and gas flow velocities in
industrial applications. The pitot tube is used to measure the local flow
velocity at a given point in the flow stream and not the average flow
velocity in the pipe or conduit.
A slender tube aligned with the flow (Figs. 6.29g and 6.30) can
Measure local velocity by means of a pressure difference. It has sidewall
holes to measure the static pressure ps in the moving stream.
Hole in the front to measure the stagnation pressure p0, where the
stream is decelerated to zero velocity.
Instead of measuring p0 or ps separately, it is customary to measure their
difference with, say, a transducer, as in Fig. 6.30.
The flow around the probe is nearly frictionless and Bernoulli’s relation,
applies For incompressible flow:
( ) ( )
Where: Ps, vs, and zs= static pressure, velocity, and elevation at the pipe
flow.
Po, vo, and zo= pressure, velocity, and elevation at the stagnation point.
vo= zero.
Assuming that zs=zo. calculating the velocity at stream flow:
( )
√
Ex 1:
1. Pitot Tube:
is a pressure measurement instrument used to
measure fluid flow velocity. The pitot tube was invented by
the French engineer Henri Pitot in the early 18th century[1] and was
modified to its modern form in the mid-19th century by French
scientist Henry Darcy.
It is widely used to determine the airspeed of an aircraft, water speed
of a boat, and to measure liquid, air and gas flow velocities in
industrial applications. The pitot tube is used to measure the local flow
velocity at a given point in the flow stream and not the average flow
velocity in the pipe or conduit.
A slender tube aligned with the flow (Figs. 6.29g and 6.30) can
Measure local velocity by means of a pressure difference. It has sidewall
holes to measure the static pressure ps in the moving stream.
Hole in the front to measure the stagnation pressure p0, where the
stream is decelerated to zero velocity.
Instead of measuring p0 or ps separately, it is customary to measure their
difference with, say, a transducer, as in Fig. 6.30.
The flow around the probe is nearly frictionless and Bernoulli’s relation,
applies For incompressible flow:
( ) ( )
Where: Ps, vs, and zs= static pressure, velocity, and elevation at the pipe
flow.
Po, vo, and zo= pressure, velocity, and elevation at the stagnation point.
vo= zero.
Assuming that zs=zo. calculating the velocity at stream flow:
( )
√
Ex 1:
