Development of a simple structure of milifluidic impedance-based sensor for speed measurement

• Main Author: Ghajar, Masoumeh Asghari
• Format: Thesis
• Language: English
• Published: 2019
• Subjects: Fluid dynamics; Microfluidics
• Online Access: http://psasir.upm.edu.my/id/eprint/85574/1/FK%202020%2020%20-%20ir.pdf; http://psasir.upm.edu.my/id/eprint/85574/

Microfluidic systems for flow sensing have been widely explored, although the processes involved in their fabrication are lithography intensive making the process quite expensive and cumbersome. The aim of this work is to fabricate a device for fluid detection and identification. Therefore the device development consists of channel and geometry parameters optimisation that are modelled by COMSOL, while further development incorporates microcontroller that allows device to read and display result on LCD and excel datasheet. Fabrication of the device does not require a complicated lab-on-chip process so device can easily be implemented. The high sensitivity sensor was obtained by sweeping the geometrical parameters of the configured electrodes in a channel to reach high amount of electric field, moreover comparisons of electrodes geometry and resulted electric fields are shown. COMSOL software is used for modelling of channel design and allows us to input mathematical parameters; this causes better analysis to understand the behaviour of fluid in this physical environment. Simulation is also based on electrode and geometry optimization with COMSOL Multiphysics for creating the sensitivity while the electrode geometry calculation is swept from different points for sensor optimization while simulation of fluid droplet carried out by dielectric material such as water. Peak signal was obtained to measure the speed of a fluid in a channel besides etching technology was also used. Data output converts to electrical reference for speed and impedance measurement analysis while Microsoft Excel spread sheet is used as data entry from Arduino side to computer side for further analysis. The study uses admittance measurement in order to understand the sensitivity of each cascade electrode for modelling as compared to the other available design using a capacitive measurement, though admittance has direct impact to its impedance once conductivity took place.