“Our expertise is needed—let’s team up and put it to good use” describes the spirit of a threeday meeting brimming with lectures, poster sessions, and discussions. More than 100 participants from several continents convened to share forefront results and develop perspectives for future research to enable cleaner combustion processes. That clean(er) combustion is important can be appreciated from the impact of combustion-generated emissions on air quality and human health. It is common knowledge that particle-loaded urban pollution affects the respiratory tract. Black carbon particles from combustion processes are also associated with climate effects that have been underestimated in the past and are now often regarded as the secondmost important factor contributing to climate change next to carbon dioxide. Gregory Smallwood (National Research Council, Toronto, Canada) in his keynote lecture emphasized substantial contributions of combustion research to reduce emissions from airborne transportation, but pointed out unknowns that depend on a precise assessment of the soot emission’s properties. That soot formation is not understood in sufficient detail was highlighted by several researchers, including the invited kick-off lecture by Hai Wang (Stanford University, USA) who posed ten questions reflecting gaps in current knowledge.
Contributions to better understanding are expected from combinations of experiment, model development and simulation. Invited presentations by Yiguang Ju (Princeton University, USA), Fei Qi (Shanghai Jiao Tong University, China), Tina Kasper (Duisburg-Essen University, Germany) and Philippe Dagaut (CNRS Orléans, France) emphasized the interplay between pushing diagnostics beyond current limits as well as establishing meaningful idealized experiments. The diagnostic complexity needed to study near-technical-scale injectors and combustors on the one side and the detection of smallest soot particles in their infant state on the other was particularly evident from contributions by Mark Linne, (Edinburgh, UK), Wolfgang Meier (DLR Stuttgart, Germany), and Pascale Desgroux (CNRS Lille, France), while recent advances in understanding catalytic aftertreatment, in combustion modeling, uncertainty assessment, and process planning were detailed in lectures by John Mantzaras (PSI, Switzerland), Heinz Pitsch (RWTH Aachen, Germany), Tiziano Faravelli (Politecnico di Milano, Italy), and Kristina Eisen (Bremen University, Germany).
Avoiding emissions in part by using fuels from biomass, presented by Terese Løvås (Trondheim University, Norway), or hydrogen, as discussed by Howard Levinsky (University of Groningen and DNV GL, The Netherlands) is not without problems, since complex infrastructural problems may result, for example, in adapting millions of household and industrial appliances to natural gas enriched with hydrogen. Intelligent use of waste in gasification and power generation was discussed as another topic needing further investigation by Franz Winter (TU Vienna, Austria).
Invited contributions were complemented by selected short lectures and rapid poster talks as well as an evening poster session. The meeting culminated in a sequence of plenary and breakout discussions, collecting results and preparing perspectives on fuels, aftertreatment, modeling, diagnostics, and cross-fertilization of combustion with other fields. Internationally different situations regarding resources, geopolitical dependencies, regulations, and status of research and technology made this exchange especially valuable. The debate stressed opportunities for joint research, especially of early career scientists, and areas were identified for in-depth fundamental research that should, however, keep an eye on relevance for solving societal problems. Regionally different needs (such as in emerging economies) received attention including affordable emission aftertreatment, efficient and clean stoves, and sensors to monitor emissions—problems deserving an open mind to address the relevant scientific issues. Overall the discussions highlighted the role of clean combustion techniques as one important element in transportation and energy conversion systems of the future, e. g. regarding hybrid electric or autonomous transportation as well as energy storage with high-density liquids.
Cleaner combustion systems: Understanding needs and details
Hai Wang Ten questions concerning mechanisms and models of soot formation
Philippe Dagaut Low-temperature chemical kinetics of alternative and conventional fuels oxidation
Howard Levinsky Why can’t we just burn hydrogen?
Pascale Desgroux About the formation of (some) pollutants in combustion processes
Henning Bockhorn Reactivity of diesel soot particles: Why is soot not alike soot
Nils Hansen New tools for flame diagnostics: Microwaves and X-rays
Combustion applications: Impact and reduction of emissions
Greg Smallwood Black carbon: Measurement challenges for climate and health impact mitigation
Heinz Pitsch Autoignition chemistry and model reduction
Terese Løvås Biofuels from thermal conversion of bio-mass, a multi-scale problem
Franz Winter Waste combustion and gasification: Implications and challenges
Chemistry for cleaner combustion: Fuels, mechanisms, and aftertreatment
Fei Qi Advanced synchrotron-based combustion diagnostics
Tiziano Faravelli Modeling the lab experiments of sooting flames
Yiguang Ju Experiments and models of low temperature combustion of alternative fuels
John Mantzaras Experiments and models for catalytic combustion
Patrick Nau IR absorption spectroscopy for temperature and concentration measurements in a gasifier
Kai Banke Combined production of power and syngas in an internal combustion engine
Physics: Tools and techniques
Mark Linne Diagnostics for dense sprays in support of predictive models
Tina Kasper Diagnostics for combustion and nanoparticle formation
Kristina Eisen Multi-quantity diagnostics for an efficient process design?
Wolfgang Meier Multi-species diagnostics at high pressure for gas turbine combustion
María Abián (Saragossa, ESP), Burak Atakan (Duisburg, GER), Brigitte Attal-Tretout (Palaiseau, FRA), Ghobad Bagheri (Mailand, ITA), Kai Banke (Duisburg, GER), Martina Baroncelli (Aachen, GER), Florian Bauer (Erlangen, GER), Christopher Betrancourt (Villeneuve d’Ascq, FRA), Thomas Bierkandt (Duisburg, GER), Henning Bockhorn (Karlsruhe, GER), Marina Braun-Unkhoff (Stuttgart, GER), Andreas Brockhinke (Bielefeld, GER), Michael P. Burke (New York, USA), Joaquin Camacho (San Diego, USA), Xing Chao (Peking, CHN), Cheng Chi (Magdeburg, GER), Philippe Dagaut (Orleans, FRA), Pascale Desgroux (Villeneuve d’Ascq, FRA), Robert Dibble (Thuwal, KSA), Thomas Dreier (Duisburg, GER), Julia Eble (Karlsruhe, GER), Sven Eckart (Freiberg, GER), Fokion Egolfopoulos (Los Angeles, USA), Kristina Eisen (Bremen, GER), Torsten Endres (Duisburg, GER), Luming Fan (Cambridge, GBR), Tiziano Faravelli (Mailand, ITA), Nancy Faßheber (Kiel, GER), Daniel Felsmann (Aachen, GER), Mustapha Fikri (Duisburg, GER), Benoît Fond (Magdeburg, GER), Gernot Friedrichs (Kiel, GER), Dirk Geyer (Darmstadt, GER), Christopher Goldenstein (West Lafayette, USA), Isabelle Graf (Bielefeld, GER), Nils Hansen (Livermore, USA), Jürgen Herzler (Duisburg, GER), Corinna Janzer (Karlsruhe, GER), Jay Jeffries (Stanford, USA), Bo Jiang (Nanjing, CHN), Hanfeng Jin (Thuwal, KSA), Yiguang Ju (Princeton, USA), Dennis Kaczmarek (Duisburg, GER), Yasin Karakaya (Duisburg, GER), Tina Kasper (Duisburg, GER), Georgios Anastasios Kelesidis (Zürich, SUI), Fethi Khaled (Thuwal, KSA), M. Reza Kholghy (Zürich, SUI), Johannes Kiefer (Bremen, GER), Sebastian Kluge (Duisburg, GER), Nicole Labbe (Boulder, USA), Nathalie Lamoureux (Villeneuve d’Ascq, FRA), Sascha Lau (Duisburg, GER), Michael Letzgus (Bielefeld, GER), Howard Levinsky (Groningen, NED), Yuyang Li (Shanghai, CHN), Mark Linne (Edinburgh, GBR), Dong Liu (Nanjing, CHN), Terese Løvås (Trondheim, NOR), Arnas Lucassen (Braunschweig, GER), Gaetano Magnotti (Thuwal, KSA), John Mantzaras (Villigen, SUI), Wolfgang Meier (Stuttgart, GER), Kai Moshammer (Braunschweig, GER), Antonella Napolitano (Neapel, ITA), Patrick Nau (Stuttgart, GER), Vaclav Nevrly (Ostrava-Vyskovice, CZE), Matthias Olzmann (Karlsruhe, GER), Patrick Oßwald (Stuttgart, GER), Warumporn Pejpichestakul (Mailand, ITA), Julia Pieper (Bielefeld, GER), Heinz Pitsch (Aachen, GER), Owen Pryor (Orlando, USA), Fei Qi (Shanghai, CHN), Mona Lisa Remmers (Bielefeld, GER), William Roberts (Thuwal, KSA), Lena Ruwe (Bielefeld, GER), Maurin Salamanca Guzmán (Bielefeld, GER), Steffen Schmitt (Bielefeld, GER), George Skevis (Thessaloniki, GRE), Nadezda Slavinskaya (Stuttgart, GER), Greg Smallwood (Ottawa, CAN), Yu Song (Nancy, FRA), Giancarlo Sorrentino (Neapel, ITA), Torsten Stärk (Dresden, GER), Nerijus Striugas (Kaunas, LTU), Alex Tagbo (Berlin, GER), Joàn Teerling (Assen, NED), Bo Tian (Cambridge, GBR), Zhen-Yu Tian (Peking, CHN), Luc-Sy Tran (Bielefeld, GER), Hai Wang (Stanford, USA), Zhandong Wang (Thuwal, KSA), Isabelle Weber (Karlsruhe, GER), Maximilian Wick (Aachen, GER), Franz Winter (Wien, AUT), Julia Wullenkord (Bielefeld, GER), Xuefei Xu (Peking, CHN), Bin Yang (Peking, CHN), Xiaoqing You (Peking, CHN), Wenhao Yuan (Shanghai, CHN), Feng Zhang (Hefei, CHN)