Can an ultrasonic flowmeter measure accurately when the medium flow velocity in the pipeline is very low (e.g., < 0.1 m/s) or very high (e.g., > 10 m/s)?

At this stage, the medium flow is close to laminar flow, with poor uniformity of velocity distribution. Single-path flowmeters, which only measure the flow velocity at the pipe center, will see their conversion error expand from ±1% to more than ±3%. In contrast, multi-path flowmeters can maintain an accuracy of ±0.5% to ±1% by measuring velocities at multiple points and calculating a weighted average. However, it is necessary to select the “specialized low-flow-velocity type” (with higher signal amplification).

High-speed flow tends to generate turbulent noise, and the time difference of ultrasonic wave propagation becomes smaller (making it difficult to capture accurately), which may lead to fluctuations in instantaneous flow. It is required to choose a “high-frequency sampling type” flowmeter (with a sampling frequency ≥ 100 Hz) and ensure tight coupling between the sensor and the pipeline (to reduce vibration interference).