The principle of ultrasonic flowmeter | Doppler ultrasonic flowmeter flow measurement principle

『The principle of ultrasonic 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)

What is the working principle of clamp type ultrasonic flowmeter? The working principle of clamp type ultrasonic flowmeter is mainly based on two techniques: time difference method and Doppler effect method, which calculate fluid velocity and flow rate through non-invasive measurement. Here are the specific principles and processes:

First, the principle of time difference method is based on measuring the flow velocity using the time difference between the forward and backward propagation of ultrasonic waves in the fluid.

. When the fluid in the pipeline is stationary, the propagation time of ultrasonic waves upstream and downstream is the same; When fluid flows, the propagation speed in the downstream direction increases (time shortens), while the propagation speed in the upstream direction slows down (time prolongs). Measurement process: Probe installation: Two ultrasonic probes are symmetrically installed outside the pipeline, one as the transmitter and the other as the receiver. Signal transmission: The transmitter emits ultrasonic shed wave signals, which penetrate the pipeline wall and fluid before being captured by the receiver. Time difference calculation: Measure the propagation time difference (Δ t) in the forward and backward directions. Flow velocity calculation: Based on parameters such as pipeline diameter (D) and fluid sound velocity (c), calculate the flow velocity using the formula V=(D/2 Δ t) × (c2/f) (where f is the ultrasonic frequency). Flow calculation: Based on the flow velocity (V) and pipeline cross-sectional area (A), the flow rate is obtained using the formula Q=V × A. Image: Xiamen Jingchuan JCUFM Clamp type Flow Meter (Time Difference Method Application Example) Applicable Scenarios: Suitable for relatively pure fluids (such as water and oil), with high measurement accuracy and little influence from fluid composition cracking.

2. Principle and basis of Doppler effect method: When ultrasonic waves encounter suspended particles, bubbles and other reflectors moving in the fluid, the frequency of the reflected wave will shift due to the fluid motion (Doppler effect).

. When the fluid moves towards the sensor, the frequency of the reflected wave increases; The frequency decreases when moving away. Measurement process: Signal transmission and reception: The transmitter cavity emits ultrasonic waves into the fluid, and some of the signals are reflected by the reflector and captured by the receiver. Frequency difference measurement: Calculate the difference between the frequency of the transmitted wave (f?) and the frequency of the received wave (f?) (Δ f=f? - f?). Flow velocity calculation: Calculate the flow velocity using the formula V=(c × Δ f)/(2f × cos θ) (where θ is the angle of incidence of ultrasonic waves). Flow calculation: Based on the cross-sectional area of the pipeline (A), the flow rate is calculated using the formula Q=V × A. Applicable scenarios: Suitable for fluids containing suspended particles or bubbles (such as sewage, mud), but measurement accuracy is affected by particle concentration and distribution.

III. Technical Features and Advantages Non invasive Installation: The probe is clamped outside the pipeline, without the need to cut off the pipeline or stop production, making installation convenient.

. High measurement accuracy: The time difference method has an accuracy of ± 1% in pure fluids, while the Doppler method has an accuracy of about ± 2%~5% in fluid

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