In hydrodynamics, a triangular column type vortex generator is set for the sample of bar type flowmeter, which creates standard vortices from both sides of the vortex generator. Such vortices are called Lenny vortices. As shown in the figure below, the vortices are arranged asymmetrically and densely in the middle and lower reaches of the vortex generator.

If the frequency of vortex occurrence is f, the mean water flow of the measured material is, the total width of the upstream surface of the vortex occurrence body is D, and the surface pipe diameter is D, the following expression can be obtained:

SR -- Strouhal number; F = sru1 / D = SRU / MD where U1 -- average water flow on both sides of the vortex generator, M / S;

M -- ratio of bow area on both sides of vortex generator to total area of pipeline section

The total flow QV of the pipeline content product is: QV = π d2u / 4 = π d2mdf / 4sr, k = f / QV = [π d2md / 4sr] - 1

Where k - instrument panel index of steam flowmeter, pulse number / m3 (P / m3).

K is not only related to the geometry specifications of vortex generator and pipeline, but also related to sewage flowmeter. The Strouhal number is a dimensionless main parameter, which is related to the shape and Reynolds number of the vortex generator. Figure 2 shows the relationship between the Strouhal number of the cylindrical vortex generator and the Reynolds number of the pipeline. It can be seen from the figure that in the range of red = 2 × 104 ~ 7 × 106, SR can be regarded as a constant, which is the category of all normal operation of the instrument panel. When measuring the gas pressure, the volume flowmeter of VSF is the correlation curve of Strouhal number and Reynolds number

PN, P -- pressure under standard state and working condition respectively, PA; where qvn, QV -- total volume flow under standard state (0oC or 20oC, 101.36677kpa) and working condition respectively, m3 / h;

TN, T -- thermodynamic temperature under standard state and working condition respectively, K;

Zn, Z -- vapor compression coefficient under standard state and working condition respectively. Henghe vortex flowmeter is a new type of steam flowmeter based on the basic principle of Lenny vortex. Because of its excellent material adaptability, the total volume flow of steam, gas, steam, water and liquid can be measured immediately without compensation of temperature working pressure. The total volume flow and mass flow of standard condition can be measured with temperature and liquid level sensors, which is an ideal substitute for throttle valve type steam flowmeter. In order to improve the heat-resistant and anti vibration characteristics of Henghe vortex flowmeter, the controller can be applied in the extreme conditions of high temperature (350 ℃) and strong vibration (< 1g) due to its unique structure and material selection.

Yokogawa vortex flowmeter is a kind of instrument panel which transforms the independent variable of working pressure into a uniform output data signal, and its output data signal has a certain functional relationship with the controller, which is a linear function.

The independent variable of working pressure includes positive, negative, differential and high-quality working pressure. The unified output data signal is 0-8ma, 4-50ma AC data signal. According to different transformation principles, Henghe vortex flowmeter can be divided into (torque) balance type, capacitance sensor, capacitance type, strain force type and frequency type, etc.