Uncertainty of vortex gas flowmeter

『Vortex gas flowmeter』Related information(clamp on meter|electromagnetic meter|venturi meterrotameter|orifice meter|ultrasonic flow meter|mass flow meter|coriolis mass flow meter|coriolis flow meter|magnetic flow meter|magmeter flow meter|magflow flow meter|mag meter flow meter|electromagnetic flow meter|vortex flow meter|turbine flow meter|thermal mass flow meter|thermal flow meter|rotameter flow meter)

1. What is the difference between a turbine and a vortex gas flowmeter?

The difference between vortex flowmeter and vortex flowmeter. Vortex flowmeter is a device that sets a stagnation piece in the flowmeter pipeline. When the fluid flows through the stagnation piece, two asymmetric vortices will be generated downstream due to the stagnation effect on the surface of the stagnation piece. These vortices will separate on the side and rear of the stagnation piece, forming a so-called Karman vortex column. The rotation direction of the two vortices is opposite. Karman theoretically proved that when h/l=0.281 (h is the width between two vortex columns, and l is the distance between two adjacent vortices), the vortex column is stable. In this case, the frequency of vortex generation The relationship between f and the fluid velocity υ in the flowmeter pipeline is: f=sv/dv=df/s, where d represents the diameter of the cylindrical stagnation component; S - dimensionless constant, called Strouhal number, related to the Reynolds number re of the fluid flow state. The Reynolds number re of a circular cross-section pipeline with a flow meter is: where υ - the flow velocity of the fluid, m/s； ρ - density of fluid, kg/m3； μ - dynamic viscosity of fluid, (kg?m-1)/s。 And the flow rate of the fluid: q=a * v can be seen from the above equation. After the selection and design of the vortex flowmeter, the flow rate q is not only related to f, but also to the Reynolds number re. The Reynolds number re is a dimensionless number that characterizes the flow characteristics of viscous fluids, and its physical meaning is the ratio of the inertial force to the viscous force of fluid flow. Therefore, the flow state of the fluid also has

a certain impact on the use of vortex flowmeters. If environmental parameters have an impact on the fluid flow state, it will also affect the performance of the vortex flowmeter. When the fluid flow sensor of the vortex flowmeter is fed along the axial direction, it is forced to rotate around the centerline under the action of the vortex generator, generating a vortex flow. The vortex flow rotates in the Venturi tube and reaches the contraction section where it suddenly throttles, accelerating the vortex flow. When passing through the diffusion section, the center of the vortex precesses along a conical spiral line. At this point, the precession frequency of the vortex center through the detection point is proportional to the flow velocity of the fluid. The precession frequency signal of the vortex flow detected by the piezoelectric sensor is amplified, filtered, and shaped before being converted into a flow value for on-site display or signal selection.

2. Uncertainty of Spiral Vortex Flow Meter

The uncertainty of Spiral Vortex Flow Meter should be analyzed separately according to its classification (Class A/B), and the core influencing factors include measurement repeatability, standard device error, etc. 1. Uncertainty analysis methods for two types of vortex flowmeters: Type A flowmeter: using the instrument K coefficient to calculate the indication error, uncertainty analysis focuses on the stability of the K coefficient and the repeatability of the flow point measurement. ② B-class flowmeter: cumulative flow is used to calculate indication error, and uncertainty needs to be introduced as variables, including measurement error and pulse counting stability.

2. The main influencing factors of unce

1. What is the difference between a turbine and a vortex gas flowmeter?

2. Uncertainty of Spiral Vortex Flow Meter

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