Pitot Tube: Working, Advantages and Disadvantages — The Engineering Knowledge

5 min readJan 12, 2021

https://www.theengineeringknowledge.com/what-is-pitot-tube/

Hi, reader welcome to a new post in this post we will have a detailed look at Pitot Tube. The pitot tube is the simplest flow sensors, it is used in a different kind of flow measurement requirements like air velocity in competing cars and fighter jets. In engineering submissions, pitot tubes are works to calculate air movement in piping, tubes, lots, and fluid movement in cylinders, barrages, and exposed stations. Though it’s precision and range capacity are comparatively little, pitot tubes are modest, dependable, cheap, and suitable for an assortment of ecofriendly circumstances, including extremely higher temperature and a varied assortment of pressure.

The pitot tube is cheap and can substitute for an orifice plate. Precision varieties from 0.5 percent to 5 percent, which is similar to that of an orifice plate. Its flow range capacity of 3:1 is also alike to the ability of the orifice plate. The important difference among the pitot tube and orifice is that, orifice plate measure the speed during its complete movement but pitot measure at one point in the flow direction

Introduction to pitot tube

The pitot tube is the simplest flow sensors, it is used in a different kind of flow measurement requirements like air velocity in competing cars and fighter jets
Pitot tube computes a fluid speed by changing the kinetic energy of the fluid into potential energy. The change occurs at the inaction point positioned at the Pitot tube entry point.
The pressure is greater than the free watercourse pressure consequences from the kinematic to potential change.
This stationary pressure is calculated by relating it to the movement’s active pressure with a discrepancy manometer.
The module was created by the French engineer Henri Pitot in 1732. Originally, it was used to calculate the speed of a river.
One chief benefit of using these pipes above other liquid pressure measuring apparatuses is that they can be directly applied over a varied variety of surroundings, like higher pressure circumstances, and extraordinary temperature situations.
The benefit of the thin pitot is that it can be implanted into prevailing and forced pipelines (named hot-tapping) deprived of demanding a stoppage.

Working of pitot tube

Fundamentally a pressure difference (d/p) meter, a pitot tube procedures two pressures first one the stationary and the other is total bearing pressure.
The stationary pressure is the employed pressure in the tube or the atmosphere, upstream to the pitot tube.
It is used at 90 degrees to the flow path, rather in a little turmoil position.
The entire bearing pressure (PT) is the calculation of the stationary and dynamic pressures and is noticed as the curving tributary effects on the pitot open point.
To calculate bearing pressure, most pitot pipes usage a lesser, occasionally L- form tube, with the inaugural straight fronting the approaching flow stream.
The print speed of tactic (VP) can be intended by captivating the square root of the alteration amid the entire pressure (PT) and the stationary pressure (P) and multiply that by the C/D proportion, where C is a constant and D denotes density fluid:

Vp= C(PT — P)½/D

When the rate of flow is found by multiply the point speed (VP) with the cross-sectional area of the pipe, it is thought that the speed measurement is prepared at an inset depth that resembles to the regular speed.
As the flow speed increases, the speed outline in the pipe deviates from extended (linear) to additional smooth (unsettled).
These vagaries the point of normal speed and needs an alteration of the enclosure distance.
Pitot tubes are optional only for extremely stormy movements (Reynolds Numbers greater than twenty thousand) and, under these circumstances, the speed outline inclines to be smooth sufficient so that the enclosure depth is not serious.In 1797, G.B. Venturi established a small tube with a throat-like way that upsurges flow speed and decreases the enduring pressure drip.
Unusual pitot enterprises are accessible that, in its place of providing just a bearing hovel for inaugural, put a single or double venturi to the bearing inaugural of the pitot pipe.

Applications Pitot Tube

In manufacturing, the flow speeds actuality calculated are frequently those curving in pipes and pipes where calculations by an anemometer would be hard to find.
In these classes of quantities, the supreme applied tool to use is the pitot tube.
The pitot tube can be introduced by a slight hovel in the tube with the pitot associated to a U-tube or some other differential pressure gauge for determining the flow speed inner side of the ducted breeze subway.
One usage of this method is to govern the dimensions of air that is being transported to a trained place.
The rate of flow of liquid can be calculated by the given formula.

flow rate = pipe area (square feet) × flow speed (feet per minute)

flow rate = pipe area (square meters) × flow speed (meters per second)

In aeronautics, air velocity is characteristically dignified in knots.
In weather places with extraordinary wind velocity, the pitot tube is changed to make a distinct kind of anemometer which is called pitot tube static anemometer.

Advantages:

It is a less cost, small meter and there is no need of any moveable part.
In this meter, there is less lasting pressure damage.
We can install it very easily.

Disadvantages:

External solid in a liquid can simply block the pitot tube and disturb usual interpretation as a consequence.
Its accuracy is Low.
Its range capability is less.

So that is a detailed post about the pitot tubes. if you have any further query ask in the comments. thanks for reading. have a nice day.

Author: Henry

http://www.theengineeringknowledge.com

I am a professional engineer and graduate from a reputed engineering university also have experience of working as an engineer in different famous industries. I am also a technical content writer my hobby is to explore new things and share with the world. Through this platform, I am also sharing my professional and technical knowledge to engineering students.

Originally published at https://www.theengineeringknowledge.com on January 12, 2021.