TRR 129: Oxyflame - Development of methods and models to describe solid fuel reactions within an oxy-fuel atmosphere (Participation)
Type of Funding: DFG Programmes, Collaborative Research Centres
To develop validated and generalized models the SFB/Transregio investigates the fundamentals of oxy-fuel combustion of solid fuels, such as coal and biomass, in a gaseous atmosphere mainly comprising CO2, H2O and O2. Replacing nitrogen by CO2 and H2O, which at high temperatures both are chemically active and strongly radiating components, results in an entirely different combustion behavior that may lead to modified chemical conversion rates, flame instabilities or even to local ignition and flame extinction phenomena. This also influences all relevant transport processes occurring on length scales ranging from atomic scale (10-10 m) to typical furnace dimensions (101 – 102 m). To identify the dominating underlying mechanisms of the transport processes, this range of scales is addressed within the SFB/Transregio both via laboratory-scale fundamental generic experiments and by larger-scale validation experiments of solid pulverized fuel combustion. Modeling approaches of different fidelity are considered ranging from molecular dynamics simulations over approaches that partially or even fully resolve the turbulence all the way to a multi-physics and multi-scale description of the system-scale with Large-Eddy Simulation (LES).Within the SFB/Transregio „Oxyflame”, internationally recognized scientists of RWTH Aachen Uni-versity, Ruhr University Bochum, and Technical University of Darmstadt are combining their expe-rience in the fields of homogenous gas combustion and heterogeneous particle combustion. Thus, high-resolution experimental and theoretical methods, previously developed and successfully applied in the experimental and theoretical investigation of gaseous combustion, can be used to inves-tigate heterogeneous particle combustion in oxy-fuel atmosphere, a process which implies a considerable increase in complexity when compared to combustion with air.The SFB/Transregio is subdivided into three project fields: Project field A (6 projects) comprises mainly the model development for reaction kinetics of solid fuel particle combustion. Project field B (8 projects) adds theoretical investigations of fluid dynamic phenomena within particle clouds, as well as investigations of the modified atmosphere’s influence on combustion. This is complemented by a cascaded set of experiments with increasing levels of complexity providing basic data for further analysis and validation. The consideration of system level phenomena including all relevant sub-processes encountered in real furnace configurations is accomplished in project field C (5 pro-jects). The central modeling activities of this project field integrate models from the other project fields, whereas the experimental work provides validation data on the system scale. Furthermore, models for the radiative heat transfer between particles and the furnace atmosphere are developed and measurements for the radiative properties of particles and walls are performed within this project field.
Contact Person at UA Ruhr:
Prof. Dr. Martin Muhler, Ruhr-Universität Bochum