As an undergraduate student in civil engineering and a discovery learning apprentice, Mac Shields worked on the reactive two-phase flow modeling project that measures flow patterns in rock structures. Originally a topic for a PhD student’s thesis, Mac took over the design and manufacture of new components for the project last fall for his supervisor, Professor Harihar Rajaram.
Mac's project simulates flow patterns in small openings of rocks by looking at the interaction of acid in those rocks and observing how the flow is affected on a non-vertical surface of the rock. Because the acid restricts water flow horizontally, the objective of the research is to determine whether it is gravitational or capillary forces that control the low-angle model, which monitors how the model responds to the two phases of fluid flow.
“By modeling this rock structure over high and low angles, we can potentially generate patterns that could be applied to larger, real-life situations. This may lead to more accurate predictions for flow in fractured rock. For example, experiments such as this could be applied to measuring the seepage of unsaturated fractured rock in Yucca Mountain, Nevada, where contaminant bomb pulse chloride has been found to depths of 350 to 450 meters,” Mac says. Each underground nuclear test explosion created a glassy cavern of fused rock and radioactive elements that are harmful to the environment. Hopefully this research data can be used with the previous results from the high-angle models to generate a complete rock structure like in the Yucca Mountains.
“There is a big difference between engineering research and practice," he says. Each trial requires a two month commitment involving the measurement of pH levels and time-lapse photography. In the first project trial, the low-angle model was found to be governed by capillary forces and these results are being used in the current trial. The entire project has included four graduate students. Mac has been a mentor to other students by helping them design and manufacture their own models in the hydraulics lab, where he says, “Sometimes the trials don’t work out, but having worked them before going into the field is critical. The new research being conducted could lead to more accurate analysis about the reactive material deposited by a bomb's pulse, and how they might react with the water entering the mountain’s fractures.” It would also allow forecasts about potential issues with water supply, especially a water supply used in urban areas.
The Discovery Learning Apprenticeship Program has opened doors for Mac to interact and connect with professors and staff beyond what a typical student might encounter. It also helped guide him in the choice of an industry after graduation. Mac currently works in Denver for Schlumberger Oil Field Services, a petroleum consulting company which has sent him around the world to destinations including Mumbai (Bombay), India, China, Kuala Lumpur, Malysia, and Dubai.