Professor's research leading to more efficient engines

Combustion is one of the most common ways of extracting energy from a substance or material. The invention of the internal combustion engine enabled mass transportation in the Industrial Revolution, and is still very widely used in everyday life in planes, trains, cars, furnaces, and gas ovens and stoves. MechSE Professor Moshe Matalon is answering essential questions about the nature of combustion, to make it easier and more efficient to make use of its energy.

"The objective is a fundamental understanding of combustion processes," Matalon said. "And understanding is crucial to anything. If you want to improve things, if you want to design things, you need to understand."

Combustion is a very complex process to model. It involves fluid mechanics when the fuel is a gas or a liquid, but becomes more complicated when a liquid fuel is evaporated and the combination of liquid and gas becomes a multiphase flow. The chemistry of the process is also quite involved, as the reaction can involve hundreds of compounds that react to each other differently. In addition, the release of heat from the reaction can change the state of the evaporated fuel and make the flow even more difficult to model.

"It’s all very coupled, and mathematically very complex," Matalon said. "Even if you use all the equations that we believe we know more or less sufficiently accurately, we have to put them into a computer because you cannot really solve them with all of their complexities in any reasonable way. So you need to adopt some simplifications and approximations in different aspects of the problem."

This field of study doesn’t limit itself to specific applications; it can be applied to everything that requires a stable flame, including most forms of traditional energy manufacturing which may use such a flame as a pilot.

One major problem with keeping a flame stable is how to deal with “turbulence” from the motion of moving parts or moving air. Almost all practical applications of combustion operate under turbulent conditions of some kind. Matalon and his group have researched how quickly a turbulent flame propagates—a property crucial to determine the mean fuel consumption rate of a combustion system. This information could be incredibly helpful for optimizing internal combustion engines and improving current models of similar systems.

"If you want to improve your engine," Matalon said, "if you want to be able to predict what your engine will do, you cannot just do it by brute force experiment. That is how engines have been developed in the last 100 years, by trial and error. You try, you improve. But in recent years, there has been more emphasis on increasing our computational ability, and it has shown us how important it is to have a fundamental understanding of these complex systems. It invariably helps the design and the improvement of the machines."