Objective:
The goal of this experiment is to study droplet generation behavior of a flow focusing device, understand the pressure level effect on droplet radius and period via video processing. Students will use a pressure pump, a 3D digital microscope and a flow focusing device to generate droplets at varying sizes. Also, they will learn fabrication of microfluidic devices.
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The experimental system comprised of Elveflow pressure pump, Microqubic 3D digital microscope and microfluidic flow focusing device (Fig.6).
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2. Pre-Lab Quiz
Quiz Date: xxxxxx: 16/12/2024
The quiz will cover the microfluidics, droplet generation devices, Navier Stokes equations, fabrication of microfluidic devices.
Please watch all the videos. You will be responsible from them as well.
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Step-by-Step Instructions:
Switch on Elveflow pump. Make sure inlet ports are closed.
Open vacuum source.
Open ESI software. Click on Calibration button. Let the system calibrate itself. Calibrate the system twice.
Switch on Microqubic 3D digital microscope.
Open Microqubic software. Choose See3Cam camera.
Under camera options adjust Exposure, set it to Auto.
Put your microfluidic chip on the stage.
Using joystick adjust focus until you observe microfluidic channels.
Connect DI and silicone oil vial to the inlets of pump.
Never let fluid to go inside pressure line.
On ESI software, click Stop All button.
Give 10 mbar pressure to the DI line. Wait until fluid comes at the edge of the precision tip.
Insert DI precision tip to the DI inlet on the microfluidic chip.
Close pressure.
Give 50 mbar pressure to the silicone oil line. Wait until fluid comes at the edge of the precision tip.
Insert DI precision tip to the DI inlet on the microfluidic chip.
Close pressure.
Go to DI inlet. Increase pressure to 20 mbar. Watch for the fluid while it is going through the microchannel. At this point you can lower the pressure, because DI should not go into the silicone oil channel. The reverse is also valid.
Go to silicone oil inlet. Increase pressure to 40 mbar. Watch for the fluid while it is going through the microchannel. At this point you can lower the pressure, because silicone oil should not go into the DI channel.
Using microscope joystick, go to the junction where droplet will be generated.
Adjust pressures accordingly until you observe droplet generation.
After droplet generation is observed, increase pressure of DI and silicone oil proportionally to observe varying size and speed droplets.
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4. Data Collection
Due Date: xxxxxx
During the lab, collect the following:
Take a note of pressure values of both DI water and silicone oil.
Take videos using Microqubic software.
Use these videos for image processing to determine droplet sizes (Code will be provided).
5. Post-Lab Report
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Use these videos for image processing to determine droplet sizes (Code will be provided).
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5. Post-Lab Report
Due Date: 19/12/2024 until 11.59 pm
The report for this part is expected to include:
Abstract and Introduction
Procedures and Steps
Experiment Related (Plots & Calculations)
Discussion and Conclusion
Submit a report plotting :
DI pressure value vs. Droplet size for 10 different DI pressure values while fixing silicone oil pressure. Do not forget to include units.Silicone pressure value vs. Droplet size for 10 different silicone oil pressure values while fixing DI pressure. Do not forget to include units.
Comparison of experimental data with theoretical predictions.
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