Instrumentation Calculators

Pitot tube flow velocity calculator

Pitot tube flow velocity calculator
  • One of the flow elements used to gauge the rate of flow in a pipeline, duct, etc. is the pitot tube. Pitot tubes are frequently utilised because of their inexpensiveness, convenience, and small size.
  • The pitot tube’s construction is based on the measurement of the process’s static and stagnation pressure in the pipe.
  • The difference between these two pressure readings indicates that dynamic pressure is just the point at which velocity becomes zero and pressure is converted.
  •  By using this idea as a guide, the Pitot Tube flow calculator was created.
  • When accuracy is minor, pitot tubes are typically employed in air ducts, flue gas paths, etc. to measure air speed.
  • Additionally, the pitot tube will frequently become clogged with the duct particle present, requiring periodic purging of the tube.
  • The high and low pressure sides of the above picture both include a hole wave passage for measuring pressure.
  • The flowing medium’s stagnation pressure is detected by the upstream sensor, while the downstream sensor detects the static pressure.
  • Both the pressure will serve as the second sensory element, similar to the transmitter’s diaphragm.
  • You can calculate the dynamic pressure from the pressure differences to get the flowing medium’s velocity.
  • The difference between static and stagnation pressure is shown on the right side of the diagram.
  •  In order to measure the static pressure while the pipe is flowing, attach a clear, straight tube to the top. Even when the pressure condition varies, the static pressure will remain the same at any point along the pipe.
  • However, if the standard Pitot Tube is inserted at the same time, the liquid level climbs above the static pressure level.
  • The flow velocity decreases to zero as soon as it enters the Pitot Tube, which is the cause.
  • The water level is raised above the level of static pressure by the velocity impact.
  • The level above the steady pressure is known as the dynamic pressure. And when these pressures are added together, you have stagnation.

How do you measure velocity pressure with a pitot tube?

Formula for calculation

The formula to calculate velocity using Bernoulli’s equals is provided below.

V is equal to sqrt (2*(static pressure minus stagnation pressure)/density).

Pitot tube flow velocity calculator formula

To calculate the flow velocity (v), you need the values of static pressure (P), density (ρ), and stagnation pressure (P0). Rearranging the equation, we get:

v = sqrt((2 * (P0 – P)) / ρ)


P is the static pressure of the fluid

ρ (rho) represents the fluid density.

v is the flow velocity

P0 is the stagnation pressure

Example calculation:


Static pressure, P = 1.2 MPa (megapascal)

Density, ρ = 1000 kg/m^3

Stagnation pressure, P0 = 1.4 MPa

Using the formula, we can calculate the flow velocity (v):

v = sqrt((2 * (1.4 MPa – 1.2 MPa)) / 1000 kg/m^3)

= sqrt((2 * 0.2 MPa) / 1000 kg/m^3)

= sqrt(0.4 MPa / 1000 kg/m^3)

= sqrt(0.0004)

v ≈ 0.020 m/s (approximately)

Therefore, the flow velocity in this example is approximately 0.020 m/s.

Pitot tube flow velocity calculator

The ease of time is determined using the below Pitot Tube flow Calculator once all inputs have been entered. 

Click here for moreInstrumentation Calculators

Sundareswaran Iyalunaidu

With over 24 years of dedicated experience, I am a seasoned professional specializing in the commissioning, maintenance, and installation of Electrical, Instrumentation and Control systems. My expertise extends across a spectrum of industries, including Power stations, Oil and Gas, Aluminium, Utilities, Steel and Continuous process industries. Tweet me @sundareshinfohe

Related Articles

Back to top button