Research for smaller and lighter hypersonic engines

The Air Force Office of Scientific Research joined forces with the National Science Foundation in awarding a $1.5 million grant to Harsha Chelliah, a University of Virginia mechanical and aerospace engineering professor, to expand the validity of turbulence models that researchers use to predict high-speed reacting flows of air and fuel in hypersonic engines. The grant is the latest in a series of awards that has placed UVA’s School of Engineering and Applied Science at the forefront of an international effort to make hypersonic flight a reality.

“The ultimate goal is to find ways to stabilize combustion over a shorter distance,” Chelliah said. “By reducing the overall length of the combustor, we will be able to decrease overall engine weight and increase the payload.”

The Air Force had also awarded Chelliah a $2.2 million grant in 2012 to explore a viable catalytic cooling system that uses a scramjet’s own fuel as a coolant. A traditional liquid coolant system capable of controlling temperatures of this magnitude would be prohibitively heavy.

The airflow inside the UVA scramjet engine test facility is moving extremely fast, from between Mach 0.6 to Mach 1.5. At these velocities, it takes just 400 microseconds to burn the fuel/air mixture. Understanding the fundamental modes of turbulence-flame interactions under these conditions is critical.