TDZC-LUB6 temperature pressure integrated vortex flowmeter

The TDZC-LUB6 temperature pressure integrated vortex flowmeter utilizes stable vortices generated when fluid flows through obstacles, and achieves flow measurement by measuring the frequency of vortex generation.

Within a certain Reynolds number range, the frequency of vortex generation is only related to the fluid velocity and is almost unaffected by changes in the measured fluid (such as temperature, pressure, density, and dynamic viscosity).

The disadvantage is that the distribution of fluid velocity and pulsating flow will affect the measurement accuracy, and when the vortex generating body is contaminated, it will also bring errors to the measurement results.

2、 Measurement principle

The theoretical basis for flow measurement using TDZC-LUB6 temperature pressure integrated vortex street flowmeter is the outstanding "Karman vortex street" principle in fluid mechanics. A non flow linear cylindrical body (such as a triangular cylinder, cylinder, etc.) with its axis perpendicular to the flow direction is placed in the flowing liquid, called a vortex generator. When the fluid flows around the vortex generator, two asymmetric but regular alternating vortex columns will be generated under the vortex generator. This is called Karman vortex street. Only when the ratio of the distance h between the two vortex columns and the distance L between the two vortices satisfies h/L=0.281, the vortex street generated is stable, and the frequency of vortex separation is proportional to the measured flow velocity of the column.

f=SrV/d

In the formula: f - frequency of vortex separation generated by cylinder measurement (Hz);

V - Column measured flow velocity (m/s);

D - width of the upstream face of the column (m);

Sr - Strouhal number. It is a constant that depends on the cross-sectional shape of the cylinder and is essentially independent of fluid properties and flow velocity. Sr：0.17～0.18。

The design column width d of the vortex flowmeter has a fixed ratio to the diameter D of the flow tube, so the average flow velocity V inside the flow tube has a fixed ratio to the column side flow velocity V

Ｖ/Ｖ=1-1.25ｄ/Ｄ

Since both d and D are known structural dimensions in the above equation, and Sr is a constant, measuring the vortex separation frequency f yields the average flow velocity inside the tube,

So as to measure the traffic Q:

Ｑ＝3600Ｆ·Ｖ (ｍ3/ｈ)

In the formula:

F - Flow area of the sensor flow body (m2);

V - Average flow velocity of the sensor flow body (m/s).

3、 Main parameters and technical indicators

1) Technical parameters:

Measurement medium: gas, liquid, vapor;

◆ Medium temperature: normal temperature -40 ℃~+350 ℃;

Pressure rating: 2.5Mpa;

The nominal diameter is DN15-DN1000 (larger than 300mm, it is an insertable structure);

Measurement accuracy: Level 1.0 for liquids and Level 1.5 for gases and vapors;

◆ Connection methods: flange card type, flange type, plug-in type;

Output signal 4-20mA, DC (two-wire system);

Power supply voltage DC24V;

◆ Instrument operating environment temperature: -25 ℃~+55 ℃ humidity: 5-90% RH;

◆ Material: stainless steel, aluminum alloy;

Explosion proof rating ExiallCT6 (intrinsic safety type), ExdiiCT6 (explosion-proof type);

◆ Protection level: IP65

2) Usage conditions and parameters:

◆ Environmental temperature: -25 ℃ to+55 ℃;

◆ Humidity: 5-90% RH;

Atmospheric pressure: 86~106kPa;

The tested fluid is a single-phase fluid or can be considered as a single-phase fluid;

The front straight pipe section is ≥ 15D, and the rear straight pipe section is ≥ 5D.