Design and fabrication of a micro-sized channel to investigate the motion of long bubbles in porous media
Abstract
Pressure drop and thin film fluid dynamics are crucial in understanding the motion of long bubbles in porous media. As this motion has been modeled extensively but not validated with experiments, this study uses microfluidic devices (known as micromodels), nitrogen, and water with a fluorescent dye to obtain high-resolution images of the motion and the fluid dynamics of a long bubble.
After designing the 2D shape of a spiral tube in microfluidic devices with AutoCAD to ensure that the injection does not place immense pressure on the walls of the model, a Si-based microfluidic device was created using direct write lithography and photolithography. Micromodel fabrication uses plasma to etch microchannels on the silicon wafer surface, which was treated with photoresist chemicals. The microchannel in the micromodel has a length of 0.97 meters, a width of 100 microns, and a depth of 35 microns. Then, anodic bonding is used under a current and high temperatures to bond a pyrex cover glass to the micromodel, sealing the flow space. After drilling perforations at the inlets and outlets, epoxy is used to attach ports to the perforations. A syringe pump is used to inject fluid into the micromodel at a fixed rate. To prepare, the micromodel is primed, filling the tubes in the micromodel with water to remove all gas bubbles. Two pressure measurement devices allow the observation of change in pressure drop as the injection continues. The Hagen-Poiseuille pressure equation calibrates the pressure drop across the micromodel and verifies the linear relationship between the volumetric flowrate and pressure drop across the fluid. Experiments are being conducted to visualize the motion of the bubble and the change in pressure drop as a function of bubble velocity. Therefore, the present work visualizes and verifies the motion of long bubbles in a micro-sized tube as theorized by previous mathematical models.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMED41B1020L
- Keywords:
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- 0805 Elementary and secondary education;
- EDUCATION