Working principle of vortex flowmeter

Project Overview

The vortex flowmeter is composed of a vortex generator, a detection probe and corresponding electronic circuits. When the fluid flows through the vortex generator, two rows of alternating vortices are formed on both sides of it. This vortex is called a Karman vortex street. (See Figure 1)

The frequency of vortex separation is directly proportional to the flow rate of the fluid and inversely proportional to the width of the body, see formula (1);

f: frequency of vortex separation;

St: dimensionless constant (Strauhal number);

V: average flow velocity of fluid in the pipe;

d: width of the upstream surface of the cylinder ;

D: Inner diameter of sensor housing.

The fluid flow velocity and instantaneous flow rate can be measured by detecting the separation frequency. The Strouhal number St is a function of the Reynolds number Re within a certain flow range for a specific columnar vortex generator, St The linear part of the function with Re is the linear measurement range of the vortex flow sensor, as shown in Figure (2). Therefore, the average flow rate and volume flow rate of the fluid in the pipeline can be determined by detecting the separation frequency f.

The number of pulses generated by a unit volume of fluid flowing through the sensor is called the instrument coefficient, represented by K, see formula (2);

K: instrument coefficient;

N: number of pulses;

Q: fluid volume.

The vortices separate alternately on both sides of the rear column, generating pressure pulsations, which subject the detection body (also called the probe) in the sensor to an alternating force. See Figure (3). The piezoelectric sensor embedded in the detection body The crystal element is subjected to the action of alternating force to generate a charge frequency signal. After being processed by the detection circuit, it is output in the form of a frequency signal or converted into a standard signal form. After matching the flow totalizer instrument and temperature and pressure sensors, the parameters can be corrected and calculated.

The above is the working principle of the vortex flowmeter. Supmea Measurement and Control Technology Co., Ltd. is a manufacturer of flow meters. For many years, it has focused on the research, development and sales of thermal energy metering and monitoring systems, flow meters, pressure instruments and regulating instruments, and has also undertaken the establishment of internal energy management systems. . The company's main products include heating network metering monitoring and management systems, smart heating network prepaid steam/hot water flow metering and monitoring systems, vortex flowmeters, ultrasonic flowmeters, magnetic inductive flowmeters, balance/orifice plates/V cones/nozzles, etc. Similar differential pressure flow meters, intelligent flow/heat totalizers, pressure transmitters, dedicated backup power supplies for UPS instruments, GPRS data transmission module products, etc. The application fields include trade settlement, heat, electricity, chemical industry and laboratories, etc. field. For more questions about vortex flow meters, please contact Supmea Measurement and Control at any time, and professional technicians will answer your questions~