At the Eindhoven University of Technology there exists a close collaboration between the Department of Mechanical Engineering (Section Combustion Technology) and the Institut für Technische Mechanik of the Aachen University (RWTH) on combustion research.
Research within the Combustion Technology section encompasses the full range from fundamentals to applications of combustion, both experimentally and theoretically/numerically. Topics included are laminar premixed combustion, reduction mechanisms, optical diagnostics, turbulent combustion, biomass/biogas, heat transfer, and the interaction of sound with combustion. Applications can be found in internal combustion engines, domestic heating equipment, and industrial burners and processes.
Research activities of the Institut für Technische Mechanik of the Aachen University are related to combustion phenomena and two-phase flows. The main topics are premixed laminar and turbulent combustion in burners and spark ignition engines, diffusion flames and spray combustion in burners and diesel engines, pollutant formation, reduction of chemical reaction mechanisms, modeling of soot and nitrous oxide formation, detonation, engine knock, and knock damage.
The use of biomass related fuels in energy production is considered as CO2 neutral and therefore effectively not contributing to the green-house effect. Therefore it is financially stimulated by governments to use ''green electricity'' and the demand is growing faster than the capacity.
An alternative way to increase the capacity is to synthesize the bio-fuels to produce bio-gas, mixtures including H2 and CO as combustibles, and to apply the biogases in the existing natural gas fired electricity infrastructure. Therefore bio-gas has to be added to natural gas in increasing amounts. However, addition of bio-gas to natural gas influences the stability and safety of the generating units considerably.
A recently granted STW (Technology Foundation) project will be conducted within a framework in which the gradual transition towards a hydrogen economy is studied. In this project new numerical models will be developed in order to determine the combustion stability of biogas/methane mixtures. In a related EET project (the Dutch Economy, Ecology, Technology programme) the laminar and turbulent burning features of mixtures of hydrogen and methane are investigated experimentally. Another project, recently granted by the EU, deals with the pyrolysis, gasification, combustion and formation of polutants in biomass furnaces.
Bio-gas addition changes combustion properties, especially the turbulent burning velocity. This has its consequences for the stability and safety. Even for arbitrary mixtures the laminar burning velocities are not well known and the influence of turbulence can not be described very accurately yet. Therefore laminar burning velocities will be determined for the mixtures considered and improved turbulent combustion models for circumstances in lean-burn gas-turbines will be developed.
Three new techniques will be investigated and incorporated by the Ph.D.-student. The chemistry will be reduced by a new method called FGM (flamelet generated manifolds) without significant loss of accuracy. The turbulence modelling will be improved by taking into account the flame stretch, flame curvature and gradient and counter-gradient diffusion with the new combustion model CFM (coherent flamelet model). Furthermore, the influence of turbulent fluctuations will be diminished by explicitly taking into account the large fluctuating scales in LES (large eddy simulation). These techniques will be implemented in a commercial CFD-code by a post-doc and an assessment will be made of the combustion phenomena and the stabilization in an actual gas-turbine.