Lab Culture: Mohamed Razi Nalim

Making today’s jet engines more efficient benefits airlines, the military and the environment.

For 15 years, the combustion and propulsion research lab of professor of mechanical engineering Mohamed Razi Nalim has been home to breakthroughs in the science behind how future airplane engines and hybrid electric car engines can become more fuel-efficient and keep their internal fire reliably alight.

A major success from this lab came in collaboration with Rolls-Royce in Indianapolis: the wave rotor combustor.

“It can significantly reduce the carbon emissions of aircraft engines and smaller, quick-response gas power plants that enable renewable power generation,” Nalim explained. “This is a technology that we believe will revolutionize gas turbine engines in different applications. We have focused on particular challenges in consistent ignition of the mixture of fuel and air.”

The small lab in the Engineering and Technology Building consists of two rooms. The first is an office setting, with computers for data simulations and creature comforts like a microwave and coffee mugs galore. The area that makes this space unique is a counter attached to four windows with blinds. A large metal box with switches and buttons is at the ready to run experiments in the adjoining room, which is full of large engine rigs, hot gas and high voltage. The experiments are initiated with this control box, and students observe safely through the windows.

Dimly lit so cameras set for Schlieren photography can pick up the sparks, jets and waves of engine ignition, the lab space has the remnants of past projects. The most recent is a rig created for the exploration of new methods to ignite fuel and air mixtures in engines. It has a transparent combustion chamber for ignition observation.

“This requires a very careful study of fluid dynamics and the chemical kinetics, which is the speed at which chemical reactions happen when you’re trying to ignite a mixture of fuel and air,” Nalim said. “We want to advance the knowledge of ignition using a jet of hot gas.”

The latest breakthrough in Nalim’s lab came courtesy of Ph.D. student Mohammad Feyz. The young researcher programmed computer simulations of hot-jet ignition as an alternative to conventional spark ignition. The work was recently accepted into the AIAA Journal, the top archival journal of the American Institute of Aeronautics and Astronautics.

“My part of the job is to simulate hot-jet ignition using mathematical modeling and supercomputer calculations,” Feyz said. “We learn from those in order to improve our actual practical techniques.

“Our understanding has been much improved since the simulations have been conducted. Now we know about the locality of the ignition as well as the timing of the ignition. We can relate those factors to practical aspects of the experience, like the fuel type or the ratio of the mixture and the temperature situation.”

With the success of Feyz’s work, Nalim’s work must continue. Engines must run cleaner and cleaner without losing power and efficiency. By plane or car, the combustion and gas dynamics research in Nalim’s lab will always be essential.

“When an engine is more fuel-efficient, it burns less fuel,” Nalim said. “It produces less harmful products like carbon dioxide and other kinds of emissions.”