ECCOMET · Efficient and clean combustion experts training

Final Activity Report Summary - ECCOMET (Efficient and clean combustion experts training)

Combustion is still a major part of energy production and conversion in Europe. Largely used for domestic or industrial applications, it is found everywhere in our modern society and contributes to the global consumption of a non renewable resource and to the release in the atmosphere of numerous pollutant chemical species. The control of combustion in terms of burner stability, fuel consumption reduction and pollutants emission requires a detailed understanding of the physical phenomena involved. Combustion is a highly non linear and complex process in which chemistry, fluid mechanics, thermodynamics, radiation and phase change are deeply coupled. The ECCOMET project focused on the particular aspect of liquid fuel burning using theoretical, experimental and numerical complementary approaches. The project therefore included research and training on fundamentals of turbulent combustion and two-phase flows, experimental techniques and observation as well as computation of both academic and industrial configurations. The project was implemented through an interrelated group, bringing together research and training expertise in the theoretical, experimental and numerical approaches, i.e. by the Institut de Mécanique des Fluides (IMFT) laboratory that had a strong theoretical background, by ONERA which was an expert in experimental and numerical research and by the host, Centre Europeen de Recherche et de Formation Avancee an Calcul Scientifique (CERFACS), with a leading position in numerical simulation and modelling of complex industrial combustion systems. In most combustors, liquid fuel is injected through a diluted spray of fine droplets, which experience turbulent dispersion, collisions and break-ups, impact on the walls, evaporation and burning. Fundamental studies in the ECCOMET project allowed toincrease our knowledge of these phenomena. The thesis of D. Wunsch addressed the issue of collision and coalescence of droplets in a turbulent environment. Z. Zeren studied the influence of the spray on the ambiant air turbulence. The interaction of droplets with walls was addressed in the thesis of M. Maglio, who studied the wetting of a surface by an impinging droplet. Finally, B. Franzelli developed chemical models for the burning of liquid fuels. Experimental work was conducted in collaboration with ONERA and IMFT. It was oriented towards the development of new measurement techniques and the characterisation of two-phase flows. B. Wagner, and later J. Fritzer, worked on the development of the use of infrared absorption to measure the fuel vapour concentration around a stream of monodisperse droplets. V. Gutierrez used more classical techniques to characterise the atomisation of a liquid sheet and observed the different instabilities and regimes which are at the origin of the breakup phenomenon. To extend the knowledge and model capabilities to multi-component polydisperse sprays evaporation, V. Bodoc conducted experimental and numerical studies at both IMFT and ONERA. The new model was validated through the comparison of numerical results with the measurements. A large part of the project was devoted to numerical simulation, which was a growing activity in the field but still required important developments. The objective was to develop a reliable and predictive solver to compute two-phase combustion in industrial configurations. Three theses contributed to this objective. A. Ozel, with application to fluidised beds, worked with IMFT on the two-fluid model. F. Jaegle and J.M. Senoner both worked on a Lagrangian approach and compared its performances to the two-fluid model on simple and complex configurations. Another important difficulty was the modelling of the atomisation phenomenon, which was addressed by D. Zuzio in collaboration with ONERA. The ECCOMET project allowed to make significant progress in the understanding, observation and modelling of two-phase combustion. New tools were developed for theoretical, experimental and numerical studies, which were subsequently available to the academic and industrial communities. Results also included the training of 12 PhD students and 12 visitors, giving them extremely valuable competences as assessed by their present career.

Data: CORDIS, © European Union