Understanding low temp combustion
Fundamental chemical knowledge will aid in predicting oxidation chemistry
by Michael Padilla
Hydrocarbons come in all shapes and sizes in nature, and their oxidation reactions can be quite complex. A fundamental understanding of this important area of chemistry requires careful and
often very challenging experiments, along with state-of-the-art theoretical calculations.
A team of researchers at Sandia’s Combustion Research Facility were up to that challenge, pushing the limits of what’s possible with experiments and theory to unravel the complexity of hydrocarbon oxidation.
By conducting experiments in engine-relevant conditions using novel equipment and methods, the team produced new fundamental chemical knowledge. This new knowledge will aid in modeling the combustion of traditional fuels and proposed new fuels, facilitating the development of future efficient engines. Detailed fuel chemistry can be used to optimize performance in emerging engine designs.
According to principal investigator Leonid Sheps, this approach is most fruitful in low-temperature combustion, below about 1,000 K, where oxidation chemistry dominates fuel reactivity.
“In this ‘autoignition’ regime, fuels with different molecular structure can react to form different products and at vastly different rates,” he says. “This is one promising strategy for engine optimization. In contrast, in the high-temperature regime the kind of chemical reactions that dominate combustion are much less sensitive to the exact identity of the fuel.”
The underlying goal of the work is to understand how the molecular structure of hydrocarbons affects their oxidation chemistry in general, and to develop ways of modeling the combustion of other fuel candidates with predictive accuracy.
About the photo: Leonid Sheps adjusts equipment in a Combustion Research Facility lab. Leonid helped develop some of today’s cutting-edge experimental methods, used to unravel the complexity of hydrocarbon oxidation. (Photo by Dino Vournas)