Woodruff School of Mechanical Engineering

Faculty Candidate Seminar


Predictive Modeling of Biofuel Blending Effects for Engineering Design of Fuel-Flexible Engines


Dr. Brandon Rotavera


Combustion Chemistry Department, Combustion Research Facility, Sandia National Laboratories, Livermore, CA


Tuesday, January 20, 2015 at 11:00:00 AM


MRDC Building, Room 4211


Dr. Caroline Genzale


Engineering design of conventional spark- and compression-ignition engines requires accurate modeling of fuel combustion, which is a multi-physics problem containing influences from fluid dynamics, multi-phase phenomena, thermodynamics, heat transfer, and chemistry. To an even greater degree than in conventional engines, next-generation engine strategies including homogeneous charge-compression ignition (HCCI), dual-fuel reactivity controlled compression-ignition (RCCI), and other hybrid approaches rely more heavily on an understanding of reaction mechanisms and chemical kinetics of fuels (or, more generally, ‘fuel reactivity’). The reactivity of fuels is highly dependent on molecular structure, such as the presence of functional groups or unsaturated carbon, and governs critical engine-operating phenomena including ignition delay times, heat release rates, and pollutant formation. Therefore, a natural extension of engine-design needs is the requirement to better understand and quantitatively model fuel effects on these and other combustion-related engineering design parameters. However, significant challenges arise in understanding the fundamental combustion properties of practical multi-component fuels and blends with biofuels. Largely, these challenges are due to non-linear effects imposed from fuel-blending and complexities associated with linking fuel-specific roles (in blends of multiple fuels) to engine processes such as ignition and emissions formation. The presentation outlines an experimental framework that systematically addresses this growing challenge of understanding composition-variation effects on combustion. The framework is divided into three different Focus Areas, which collectively serve three primary purposes: (i) characterization of fuel-decomposition and combustion trends of single-component fuels; (ii) design of blended-fuel experiments using single-component fuel results; (iii) defining of rigorous experimental targets for computational modeling of blended-fuel combustion. Some broad-context energy questions to be addressed during the course of the presentation include the following: How much detailed information is really needed to model and understand combustion? Why do biofuels matter, and what does the ideal biofuel molecule look like? How much of an impact can biofuels really have, and what is the measure of impact? Why are multiple sources of biofuels sought after? Isn’t ethanol sufficient?


Dr. Brandon Rotavera holds a Postdoctoral Appointee position in the Combustion Chemistry Department at the Combustion Research Facility of Sandia National Laboratories in Livermore, CA and is a Research Affiliate at Lawrence Berkeley National Laboratory in Berkeley, CA. Dr. Rotavera received his BS in Mechanical Engineering, with a focus on thermofluids and energy, from the University of Central Florida in 2006 and an MS in Mechanical Engineering from Texas A&M University in 2010. Dr. Rotavera received his Ph.D. in Interdisciplinary Engineering, focusing on Physical Chemistry and Mechanical Engineering, from Texas A&M University in 2012, and prior to joining Sandia National Laboratories was a Research Scholar at Centre National de la Recherche Scientifique (CNRS) in Orléans, France, working at the Institute of Combustion, Aerothermodynamics, and Environmental Chemistry. Dr. Rotavera’s research efforts bridge engineering with chemistry to reveal key insight into the fundamental combustion tendencies of hydrocarbons and next-generation biofuels for the development of numerical models that contribute to the design of fuel-flexible engines.


Refreshments will be served.