Pitot tube explanation | Pitot tube uses | Pitot tube types | Pitot tube working principle.

A pitot tube is a flow measurement device that is commonly used in the aeronautical and engineering fields to measure the speed, or velocity, of fluid in a pipeline or conduit, such as air or water. The device was first developed in the 1700s by French engineer Henri Pitot, hence the name pitot tube.

The pitot tube consists of a small, open tube that is inserted into a moving fluid (such as air) perpendicular to the flow direction. The tube has a nose, called the pitot head, that is positioned facing into the flow. When the fluid flows past the pitot head, it creates a pressure difference between the pitot head and the outer surface of the tube. This pressure difference is called the dynamic pressure and is directly proportional to the velocity of the fluid.

Pitot Tube Diagram

The pitot tube also has a second tube that is parallel to the first tube but has small holes, called static pressure ports, along its sides. This second tube measures the static pressure of the fluid, which is the pressure of the fluid at rest or not in motion.

Using the difference between the dynamic pressure and the static pressure, the velocity of the fluid can be calculated using Bernoulli's equation, a fundamental principle in fluid mechanics that relates pressure, velocity, and potential energy.

The pitot tube uses in a variety of applications, including aviation, where it is used to measure the airspeed of an aircraft. In this application, the pitot tube is mounted on the exterior of the aircraft and connected to the cockpit airspeed indicator. The airspeed indicator displays the velocity of the aircraft based on the dynamic pressure measured by the pitot tube.

In addition to measuring airspeed, the pitot tube uses in water flow measurements, such as in hydroelectric power plants, where it is used to measure the velocity of water flowing through a penstock, or pipe, to calculate the power output of the plant.

Pitot tubes are also utilized in wind tunnels for aerodynamic testing, where the tube is mounted in the test section of the tunnel and connected to pressure transducers to measure the dynamic and static pressures of the airflow over a model.

There are several types of pitot tubes, including standard pitot tubes, l-shaped pitot tubes, and modified pitot tubes. The choice of pitot tube depends on the specific application and the type of fluid being measured.

Despite its widespread use, the pitot tube is not without its limitations. One of the main limitations is the effect of turbulence on the accuracy of the measurement. When the fluid flow is turbulent, the dynamic pressure may be affected by eddies and fluctuations in the flow, leading to a less accurate measurement of velocity.

In addition, ambient conditions, such as temperature and humidity, can also affect the accuracy of the measurement. For example, if the temperature of the fluid is too high or too low, it can affect the dynamic pressure measurement, leading to an inaccurate measurement of velocity.

Overall, the pitot tube is a simple and reliable way to measure fluid velocity and has many applications in various fields. As our understanding of fluid mechanics continues to evolve, the pitot tube will likely continue to play an important role in measuring fluid flow.

In fluid mechanics, a pitot tube is a device used for measuring the fluid velocity at a specific point in a fluid stream. It works based on the concept of Bernoulli’s principle, which states that the pressure of a fluid decreases as its velocity increases.

A pitot tube consists of a thin, hollow tube with a small opening (the stagnation point) facing into the fluid stream. When the fluid flows into the pitot tube, it comes to rest at the stagnation point, causing the pressure to build up and become the total pressure of the fluid. The fluid then continues to pass through the tube and exits through another opening, known as the static pressure port. The pressure in this opening represents the static pressure of the fluid.

By measuring the difference in pressure between the total pressure and static pressure, the velocity of the fluid at the stagnation point can be calculated using Bernoulli’s equation. This information can then be used to determine various fluid properties, such as the flow rate and direction, and is commonly used in applications such as aircraft instrumentation, weather monitoring, and fluid flow measurement in industrial processes.

The pitot tube consists of a small tube, open at one end facing directly into the fluid flow, and a pressure sensor located at the other end of the tube. When the fluid flow enters the open end of the tube, it is forced to slow down as it collides with the internal walls of the tube. This causes an increase in static pressure in the tube. 

Pitot tube uses: -

A pitot tube uses in fluid dynamics to measure the velocity and pressure of a fluid, specifically air or water. It is commonly used in aviation to measure airspeed and in fluid dynamics research to measure the flow rate of fluids through pipes and channels. Other Pitot tube uses of the pitot tube include:

1. Measuring velocity and pressure in wind tunnels: Pitot tubes are often used in wind tunnels to determine the aerodynamic properties of aircraft and other objects.

2. Measuring flow rate in water treatment plants: Pitot tubes can be used to determine the rate of flow of water in pipes, which can help water treatment plants determine if they are meeting the required flow rates.

3. Monitoring water levels in streams and rivers: Pitot tubes can be used to determine the flow rate of water in rivers and streams, which can help scientists and engineers understand the behavior of these water sources and determine how to best manage them.

4. Testing the performance of propellers: Pitot tubes can be used to measure the airflow around a propeller, which can help design better, more efficient propellers.

5. Measuring the speed of boats and ships: Pitot tubes can be used to determine the speed of boats and ships, which can be useful for navigation and safety purposes.

Therefore, by measuring the dynamic pressure using the pitot tube, the velocity of the fluid flow can be determined. This principle is used in many applications such as aircraft speedometers, wind tunnels, and fluid flow measurements in pipes.

Pitot tube types: -

1. Conventional Pitot tube: This is the most basic type of pitot tube that has a single open tube design. It has a static pressure port and a stagnation pressure port, which are located at the tip of the tube. It is used for measuring the velocity of a fluid.

2. Averaging Pitot tube: This pitot tube has multiple ports along the length of the tube and is used for measuring the average velocity of a fluid flowing in a pipe.

3. Pitot-static tube: This pitot tube has two tubes – one for measuring the stagnation pressure and the other for measuring static pressure. The difference between these two pressures is used to determine the velocity of the fluid.

4. Swirl-Pitot tube: This pitot tube has an additional feature that provides swirl control by rotating the flow of fluid to flow along a particular axis. It is used for measuring swirl velocities in fluid flow.

5. Total Head Pitot tube: This pitot tube has an additional tube that is inclined to measure the total head or energy in a fluid flow.

6. Multi-hole Pitot tube: This pitot tube has multiple openings or ports for measuring both static and stagnation pressures simultaneously. It can measure velocity and pressure in a fluid flow with high accuracy.

Pitot tube working principle: -

A pitot tube is a device used to measure the speed and direction of a fluid flow, such as air or water. It works on the principle of Bernoulli's equation, which states that the total pressure of a fluid is the sum of its static pressure and dynamic pressure. 

The pitot tube consists of a small tube, open at one end facing directly into the fluid flow, and a pressure sensor located at the other end of the tube. When the fluid flow enters the open end of the tube, it is forced to slow down as it collides with the internal walls of the tube. This causes an increase in static pressure in the tube. 

At the same time, the fluid flow continues to move past the open end of the tube, creating a low-pressure area due to the Bernoulli effect. This results in a decrease in dynamic pressure within the tube.

The pressure sensor at the other end of the tube measures the total pressure of the fluid, which is a combination of the static and dynamic pressure. By subtracting the static pressure from the total pressure, the dynamic pressure can be calculated. The dynamic pressure is directly proportional to the velocity of the fluid flow.

Therefore, by measuring the dynamic pressure using the pitot tube, the velocity of the fluid flow can be determined. This principle is used in many applications such as aircraft speedometers, wind tunnels, and fluid flow measurements in pipes.

Que. Pitot tube measures which pressure

Ans - the static and the total impact pressure.

Que. Pitot-static tube measures

Ans - A pitot static tube is used to measure the velocity of air flowing through a duct.

Que. Prandtl pitot tube measures

Ans - Velocity at a point in the flow.