Graduation Semester and Year
Spring 2026
Language
English
Document Type
Thesis
Degree Name
Master of Science in Chemistry
Department
Chemistry and Biochemistry
First Advisor
Purnendu K. Dasgupta
Second Advisor
Peter Kroll
Third Advisor
Charles Phillip Shelor
Abstract
Considering the importance of small flow rate measurements, this research work focused on developing a cost-effective, simple, miniature designed droplet counter system to measure small flow rates. The system involved two microscale Stainless Steel tubes facing opposite to each other and a vacuum-assisted mechanism for droplet generation and detachment. When water was passed through the system at 10 psi using a pneumatic pressure vessel, the flow rate was found ~18.8 nL/min, assuming the droplets to be cylindrical, with distance between two SS tubes set at approximately, 80 µm. This result was supported with minimal difference, by another flow rate measurement method known as gravimetric analysis. For further validation, a commercial calibrated Sensirion flow sensor was connected in series with the drop counter following a specific tubing connection. However, as suggested by the manufacturer, the Sensirion flow sensor can measure flow rates as low as 70 nL/min with highest accuracy and below this the accuracy isn’t guaranteed. Thus, the sensor can’t be used as a reliable reference.
To enable real-time detection, an inexpensive circuit was integrated into the system. The frequency of the droplets was found around 4.2 Hz which was validated by comparing it with frequency obtained from the video recording of the droplets, confirming the circuitry was functioning correctly. Additionally, experiments with ethanol-water mixtures suggested that the droplet formation of developed system is influenced by a combined effect of surface tension, viscosity and density. Overall, the developed droplet counter demonstrates significant potential as a simple, effective, and low-cost system for measuring ultra-low flow rates and future microfluidic applications. However, further studies are necessary to better understand the different parameters affecting the droplet formation in the system and improve the overall performance.
Keywords
Microfluidics, Digital Droplet Flowmetry, Drop Counter, Suction-Based Approach, Stainless Steel Tube, Surface Tension
Disciplines
Analytical Chemistry | Chemistry
License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Recommended Citation
Hasan, Mahmudul, "Measurement of Small Flow Rates Using a Noble Droplet Counter System" (2026). Chemistry & Biochemistry Theses. 3.
https://mavmatrix.uta.edu/chemistry_theses2/3