Vortex Flow Meters

The vortex flowmeter uses the principle of fluid oscillation to measure flow. When the fluid passes through the vortex flow transmitter in the pipeline, two rows of vortices proportional to the flow velocity are alternately generated up and down after the vortex generator of the triangular column. The release frequency of the vortex is proportional to the flow rate. The average velocity of the fluid flowing through the vortex generator is related to the characteristic width of the vortex generator, and can be expressed by the following formula:

where: f is the release frequency of the vortex, unit in Hz; v is the average velocity of the fluid flowing through the vortex generator, unit in m/s, d is the characteristic width of the vortex generator, the unit is m; St is the Strouhal number, dimensionless, and its numerical range is 0.14-0.27.

St is a function of Reynolds number

When the Reynolds number Re is within the range, the value of St is about 0.2. In the measurement, try to satisfy the Reynolds number of the fluid at

and the vortex frequency at this time is

Thus, by measuring the frequency of the vortex, the average velocity “v “of the fluid flowing through the vortex generator can be calculated, q=vA, and then the flow rate “q” can be calculated from the formula, where “A “is the cross-sectional area of the fluid flowing through the vortex generator