August 28, 2012
The Center for Aeromechanics Research (CAR) at The University of Texas at Austin has received a $1.3 million dollar grant from the Air Force Office of Scientific Research (AFOSR) through its new initiative that aims to approach fluid mechanics from a more fundamental level.
Professor Philip L. Varghese, CAR Director and Principal Investigator, says the main objective of the research work is to test a new concept: Can we use non-equilibrium chemistry to control the performance of complex reacting flows? If successful this technique could be used to improve the performance of scramjet engines, advanced jet engines, or even in the synthesis of new materials. Specifically, the team will be examining whether exciting molecular vibrations affects both chemical reaction rates as well as turbulent flows. It is well known that these excited molecular vibrations affect chemical reaction rates, but more research needs to be done to understand the details; whether they affect turbulent flows is still a very open question.
The multidisciplinary research team is made up of engineers and computational chemists who will combine their research results from both disciplines. Co-Investigators include Professor Noel Clemens and Associate Professor Venkat Raman, both of the Department of Aerospace Engineering and Engineering Mechanics, and Dr. Chris Simmons of the Institute for Computational Engineering and Sciences at The University of Texas at Austin. Associate Professor Wesley Allen of Chemistry at the University of Georgia (UGA) will also be working on the project. In addition, three to four UT graduate students and one UGA graduate student will be involved in the research.
“We are hoping that a unique combination of sophisticated laser measurements with state-of-the-art quantum chemical calculations and direct numerical solution of turbulent flow fields will provide some breakthroughs in our understanding and control of the chemistry-turbulence interaction process,” Varghese said. “Turbulent flow energy cascades from large scales to small scales, but chemical energy is released at the finest scale – the molecular scale – and can then feedback up the chain to the large scales.”
Varghese says the distinction between engineering and chemistry/science is blurred.
“I like to think of scientists as those who learn how nature behaves, while engineers apply knowledge of how nature behaves in order to develop useful things or to improve them. In practice, engineers also discover new knowledge and scientists can develop useful things,” Varghese said.
Both chemists will work in conjunction with Raman on such problems as calculations of quantum-state-specific reaction cross-sections for molecules that are important in hydrogen combustion – information that is extremely hard to obtain directly from experiments. Varghese will also work with the chemists and Raman to condense this information into forms that can be used for flow-field calculations.
Clemens and Varghese will work together on flow-field measurement experiments in laminar flames and turbulent flames and flows, with Clemens leading the flow-field measurements and Varghese spearheading the vibrational state-specific measurements.
Because the researchers cannot hope to measure everything, they will combine their measurements with detailed flow calculations that will examine all the details in some simplified flow situations. Raman will work on this portion of the research.
If the results are as researchers hope for, their work will not only lead the way to increased performance and efficiency in aircraft engines, but will be useful in many other industrial applications such as automobile engines, gas turbines, industrial furnaces and more.
