The vortex flowmeter measures fluid flow based on the Karman vortex principle, using a non streamlined generator to generate vortices with frequency dependent on flow velocity. Sensors detect pressure pulsations, output frequency or standard signals, and calculate flow rate and flux.

What is a vortex flowmeter and its working principle

Vortex flowmeter, also known as vortex flowmeter or Karman vortex flowmeter, is a volumetric flowmeter that measures the volume flow rate, standard condition volume flow rate, or mass flow rate of gases, vapors, or liquids based on the Karman vortex principle. It can be used as a flow transmitter in automation control systems. Here is an introduction to its working principle:

Karman vortex street phenomenon: When a non streamlined symmetrical shaped generator is set up in a fluid, such as a triangular column, and the fluid passes through the generator at a certain flow rate, two staggered columns with opposite rotation directions will be generated on both sides behind it. This phenomenon is called Karman and is stable under certain conditions. The columns are asymmetrically arranged downstream of the generator.

The relationship between vortex frequency and flow velocity: The release frequency of vortices is related to the average velocity of the fluid flowing through the vortex generator and the characteristic width of the vortex generator, which can be expressed by formula (or). Among them, represents the frequency of the vortex, represents the Strouhal number (which is a dimensionless constant related to the shape, size, and Reynolds number of the vortex generator. Within a certain Reynolds number range, it is a constant for a specific shape of the vortex generator), represents the flow velocity of the fluid, represents the width of the vortex generator, and represents the nominal diameter of the sensor.

Flow measurement principle: Vortex flowmeters typically use piezoelectric stress sensors to detect pressure pulsations generated. When the two sides of the body alternate and separate, pressure pulsation will occur, which will act on the detection body in the sensor, causing it to be subjected to alternating force. After being subjected to alternating force, piezoelectric crystal components buried in the detection body will generate charge frequency signals. After being processed by the detection circuit, these signals can be output in the form of frequency signals or converted into standard signals (such as 4-20mA current signals). By measuring the frequency and combining it with known parameters such as the Strouhal number, the width of the generator, and the nominal diameter of the sensor, the flow velocity of the fluid can be calculated. Then, the flow rate of the fluid can be calculated based on parameters such as flow velocity and pipeline cross-sectional area