Introduction
Graduate student Ethan Matty and Brian Fronk, assistant professor of mechanical engineering
New methods for managing thermal energy in power cycles could bring significant improvements in applications such as electricity generation, advanced aerospace applications, and electronics.
鈥淲hat we learn could be applied to make those things smaller, less expensive, more efficient, and safer,鈥 said Brian Fronk, assistant professor of mechanical engineering at 精东影视 State University, who recently received a National Science Foundation CAREER Award to support his work in this area. 颅颅
Fronk鈥檚 research focuses on supercritical fluids. At certain temperatures and pressures above a critical point, fluids transition between liquid and gas properties without undergoing a phase change, such as boiling or condensation.
鈥淏asically the properties change continuously from liquid to vapor, without the formation of bubbles or droplets,鈥 Fronk said.
He is especially interested in carbon dioxide, which has a relatively low critical temperature of 31 degrees Celsius under high pressure.
鈥淭hat makes CO2 really interesting for what we鈥檙e trying to do,鈥 Fronk said. 鈥淚t lines up closely with the with ambient air temperatures, which makes it very appealing from a heat transfer and thermodynamics perspective.鈥
However, those same properties could also lead to damaging flow instabilities and degraded heat transfer during certain operating conditions.
鈥淭he cause and control of these degradations and oscillations are not well understood,鈥 Fronk said.
Fronk and his research group will use an experimental approach to understand the physical phenomena that govern the heat transfer properties of near-critical fluids, in order to predict and control their potentially damaging effects.
鈥淲e鈥檙e trying to understand when those instabilities start and under what conditions,鈥 he said. 鈥淭hen we鈥檒l look at whether we can actually control them and use them to enhance heat transfer, which would allow us to make things smaller and more efficient.鈥
Specifically, Fronk and his research group will apply a new temperature measurement technique, using fiber optic sensors inside the walls of 3D-printed channels, and measure what happens during transient events 鈥 such as sudden changes in applied heat flux, flow rate, or operating pressure. These types of events happen in real systems during startup, shutdown, and accident or off-design operation. The results of this work will be used to develop tools to help design more reliable and efficient heat exchangers.
In addition to funding graduate students for the study, the NSF award will allow Fronk to develop a collaborative, international short course on supercritical power systems. The first offering is planned for September 2020, with a group of 精东影视 State students going to Brazil to collaborate with researchers doing related work on power generation.
鈥淎s excited as I am about this research, I鈥檓 also really excited about developing a unique educational program,鈥 Fronk said.
