### Basic Research Needs for Clean and Efficient Combustion of Alternative Fuels ###

1. Office of Basic Energy SciencesOffice of ScienceU.S. Department of Energy BASIC ENERGY SCIENCES -- Serving the Present, Shaping the Future A Workshop on Basic Research Needs for Clean and Efficient Combustion of Alternative Fuels* Eric Rohlfing Chemical Sciences, Geosciences, and Biosciences Division BESAC Meeting February 16, 2006 *Tentative Title http://www.sc.doe.gov/bes/

2. Workshop motivation & background • Alternative Fuels: Fuels other than those produced by refining light, sweet crude oil. Alternative fuels include those derived from renewable resources, such as biodiesel or ethanol, and fuels obtained via Fischer-Tropsch chemistry applied to heavy crude, shale oil, tar sands, and coal. • The U.S. is likely to utilize these fuels in internal combustion (IC) engines for transportation after traditional fuels (gasoline, diesel fuel) are exhausted and before hydrogen can be utilized. • DOE and other agencies are supporting research into enhancing the production of alternative fuels from renewable resources (biomass). • But, we do not know the impact with regard to efficiency and pollutant formation of the widespread use of these fuels, particularly in the next-generation of high-efficiency, low-emission IC engines. • Conclusion: A basic research program on the clean and efficient combustion of alternative fuels that assesses their potential impact on modern IC engines is needed.

3. Tentative workshop details • Basis: The strong BES program in gas-phase chemistry, combustion diagnostics, and combustion simulation. • Organization: Co-chairs from the Sandia Combustion Research Facility (Andy McIlroy) and from academia in area of combustion/engine research. Breakout sessions TBD – associated with technology challenges with science crosscuts? Participants (~75) from national labs & academia, spanning range of fundamental chemistry and applied combustion/engine research Timing and location: Fall 2006 (October) in DC area • Coordination with EERE Office of Freedom Car and Vehicle Technologies Initial positive response from program manager (Ed Wall) and chief scientist (Jim Eberhardt)

4. Enols are alchohols with an adjacent double bond Postulated in 1880 by Erlenmeyer Seen by NMR in 1973 and in gas phase in 1976 Enols not currently in flame chemistry models Work by team of BES-funded researchers on the Chemical Dynamics Beamline at the ALS (BL 9.0.2) using molecular beam flame sampling with tunable VUV photoionization reveals the presence of enols in many flames New chemistry needed to explain role of enols Shirley Award for most outstanding paper from ALS in 2005 New Experimental Tools Reveal New Class of Flame Intermediates Advanced Light Source

5. New simulation tools for turbulent combustion • Direct Numerical Simulation of a 3D Turbulent CO/H2/Air Jet Flame with Detailed Chemistry • World’s largest DNS with detailed chemistry – generated ~30 terabytes of data! • FY05 INCITE Award of 2.5 million CPU hours at NERSC; S3D code development via SciDAC; scales well on all platforms, including leadership class machines at ORNL • Investigate fine-grained coupling between turbulent mixing and finite-rate chemistry: • Extinction and re-ignition dynamics • Mixing time scales • Preferential diffusion • Physics at dissipation scales • Benchmark dataset for validation of more approximate models that might be applied to engines, i.e., large-eddy simulations. z z x x y y x air fuel air Molecular mixing in a planar jet flame

6. Laser diagnostics applied to real diesel engines • Diagnostics developed under BES support enable EERE sponsored engine research • Multiple laser diagnostics (PLIF and LII) reveal evolution of diesel spray combustion