Yes. Single-path ultrasonic flowmeters typically measure the flow velocity at the center of the pipeline and then convert it to the average flow velocity across the pipeline cross-section using an “average velocity coefficient.” This coefficient is based on the assumption of a “fully developed flow” (where the velocity follows a logarithmic distribution). However, in large-diameter pipelines, when the flow rate is low (in laminar or low-turbulence conditions with a Reynolds number < 2300), the velocity distribution is closer to a parabolic shape. As a result, the conversion error of single-path meters (from center velocity to average velocity) expands from ±1% to more than ±3%.
In contrast, multi-path flowmeters (e.g., 4-path or 8-path) measure the flow velocity at different radial positions and calculate the weighted average, which can more accurately reconstruct the cross-sectional velocity distribution. Even under low flow conditions, their accuracy can remain stable within ±0.5%.
Therefore, when measuring low-velocity media (such as in water supply networks or sewage main pipes) in large-diameter pipelines, the accuracy advantage of multi-path flowmeters becomes more pronounced as the flow rate decreases.
Post time: Sep-25-2025