PhD abstract
The metrological traceability of liquid flow rate measurements is ensured by an uninterrupted chain of calibrations against national primary and transfer standards. However, for flow rates that fall below a few microliters per minute, traceability becomes difficult due to the lack of references at this scale. In this work, and as part of the ≪Metrology for Drug Delivery II≫ European joint research project, we developed a primary system for the measurement of low liquid flow rates based on the optical tracking of a liquid/air interface moving inside a glass capillary tube. A quantification of the physical phenomena occurring at the interface and an assessment of the different uncertainty components were carried out. In order to ensure the traceability of flow rate measurements, a camera calibration procedure has been established and a method for measuring the inner diameter of capillary tubes has been developed. The system allows the calibration of liquid flow generating and measurement devices such as drug delivery systems, flow sensors, pressure controllers and syringe pumps. These devices are used for e.g. medical and microfluidics applications. Our system also enables the study of flow rate fluctuations and thus, a complete characterization of flow generating devices. As part of the external validation of the system, CETIAT participated in an interlaboratory comparison which consists in the calibration of different flow meters and a flow generator, from 5 nL/min to 1500 nL/min, for both static and dynamic flows. The results of the comparison show a measurement-expanded relative uncertainty ranging from 12 % at 10 nL/min to 0.15 % at 1500 nl/min. These measurement and calibration capabilities (CMCs) were peer-reviewed and validated by BIPM’s (International Bureau of Weights and Measures) approval process. This validation represents international recognition of our system as the French national primary standard for liquid nano-flow rates.
Keywords
interface tracking, nano-flow rate, primary standard
PhD Thesis
Full document (EN): https://pastel.hal.science/tel-04187912v1/file/ESPCI_BOUDAOUD_2022_archivage.pdf