International research partnership seeks to predict and prevent major engine problem

Alex Taylor and Anna Misley both grew up far from Ohio—Taylor in California’s Bay Area and Misley in Genoa, Italy—but the two PhD students are now in the Buckeye state helping to solve a major problem with internal combustion engines, thanks to a National Science Foundation research grant awarded to Mechanical Engineering Associate Professor Marcello Canova.

Also a faculty researcher at Ohio State's Center for Automotive Research (CAR), Canova received a prestigious five-year CAREER award from NSF in part to develop ways to model and predict surge in centrifugal compressors.

Surge is an aerodynamic instability that occurs in turbocharged engines, leading to loss of power and increased vibration and noise. If it occurs for a long duration, surge can destroy the turbocharger altogether. Engine designers and systems integrators are generally able to prevent the occurrence of surge by adopting several design and control solutions. On the other hand, because the phenomenon of surge is still not well understood, the methods currently adopted in practice are overly conservative, ultimately causing limitations to the engine performance and fuel economy. To improve the current state of the art, it is necessary to experimentally investigate the physical phenomena that lead to surge in automotive turbochargers, and develop models able to predict them.  

To do so, Canova knew he would need to recruit PhD students with diverse yet complementary skill sets. Taylor’s background in engineering and passion for applied mathematics plus Misley’s experimental background in thermodynamics and fluid machinery made for a perfect team.

“When I saw Alex’s graduate school application I immediately contacted her, and Anna is visiting from the University of Genoa, which is known internationally for their research and testing on internal combustion engines. This is the best team I could hope for,” said Canova.

Taylor and Misley are working together to create and validate a physics-based model using data Misley collected at Genoa during the first year of her PhD program. The data came from a turbocharger operating under various conditions, including stable, transient and unstable operations. “There is research on what happens during surge,” said Misley, “but not much on the transition into it. We want to be able to predict the behavior of the compressor and prevent surge before it happens.”

The existing high-fidelity physics based models are slow, sometimes taking weeks or months to compute; on the other hand, the control-oriented models that compute in real time are not accurate enough. “We have to reduce computation time. If we simulate our compressor running for one second, we want it to compute in one hundredth of a second,” said Taylor. To validate their new model, she will accompany Misley back to Italy during the 2018-19 academic year to do a second experimental run and continue to develop the modeling work started at CAR.

Already the research team has had a major success, with Misley presenting a paper on surge at the April meeting of the Society of Automotive Engineering World Congress in Detroit, Michigan—one of the largest conferences in the discipline.

The PhD students' type of interdisciplinary partnership represents the way engineering research will be conducted in the future, said Canova. “We’re creating a new generation of engineers who have the ability to bring together different fields of science to solve more and more complex problems.” The fact that this particular team consists of two women—a rarity in the often male-dominated field of automotive engineering—is a bonus.

“The gender gap in engineering seems to be decreasing, and the amount of cultural diversity is very high at CAR,” noted Misley. Whether it is asking questions about research or spending time together after work, both Taylor and Misley enjoy conversing with people with different backgrounds and experiences. “Diversity is really vital for science. By working in a multi-cultural and multi-disciplinary environment such as CAR, we can all benefit from different points of view.”