Novel Online Measurement Method for Minuscule Liquid Flow Rates

doi:10.3901/JME.2025.06.066

Abstract

Abstract: To address the challenges encountered in measuring very small liquid flow rates(≤1mL/h), a novel method for the online measurement of minuscule liquid flow rates is proposed. The method involves the analysis of visual information to determine the rate of change in the morphological dimensions of droplets at the pipe outlet under conditions of extremely low flow, where the liquid is in a dripping state. This rate of change is then used to investigate the relationship between these measurements and the velocity of the liquid within the pipe. To address the measurement errors resulting from minute droplet oscillations and non-axial symmetry at extremely low flow rates, a hexagonal prism cavity has been developed. Combined with three groups of visual acquisition units and a synchronous trigger controller, the multi-angle synchronous acquisition of dynamic volume visual information data of suspended droplets can be realised. The verification of multi-parameter symmetry is proposed, along with an optimised droplet volume measurement algorithm based on multi-angle acquisition, to further enhance the precision of system measurements. The experimental outcomes demonstrate that the droplets produced by the system exhibit good axial symmetry even at very low flow rates. The multi-view droplet volume measurement optimization algorithm improves accuracy by 2.39% over single-view methods and reduces repeatability by 0.357%. Both measurement precision and repeatability are sustained at high levels across a flow rate range of 0.8 to 60 mL /h. Through extensive experimental verification, this method for measuring very low liquid flow rates is proved to be efficient, convenient, and highly accurate, offering significant potential for application and providing a referential approach for the measurement of ultra-low flow rate rates.

Key words: minuscule liquid flow, visual information, multi-view simultaneous acquisition, symmetry verification

CLC Number:

TH814

HUANG Danping, WANG Jingdan, LUO Fan, LIAO Shipeng, GAN Fangji. Novel Online Measurement Method for Minuscule Liquid Flow Rates[J]. Journal of Mechanical Engineering, 2025, 61(6): 66-78.

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