Global sensitivity analysis of detailed chemical kinetic schemes for DME oxidation in premixed flames

Detailed chemical kinetic investigations on dimethylether oxidation in one-dimensional premixed flat flames were performed. Local and global sensitivities of the reaction rate constants within selected chemical kinetic schemes were studied using maximum flame temperature, and peak methane and formaldehyde concentrations as predictive target quantities. The global sensitivity analysis was based on the application of high dimensional model representations using quasi-random sampling. First- and second-order sensitivity indices of important reaction steps were determined for fuel rich (Φ = 1.49) and fuel lean (Φ = 0.67) conditions. Differences in the importance ranking for key reactions were found to exist between the selected schemes, highlighting the influence of differences in the key rate constants. Whilst the peak flame temperature was predicted with fairly low uncertainty by both schemes, significant uncertainties were identified in the prediction of the target minor species. Key reaction rates requiring better quantification in order to improve the prediction of methane and formaldehyde concentrations are identified

Experimental investigations and numerical simulations of methane cup-burner flame

Pulsation frequency of the cup-burner flame was determined by means of experimental investigations and numerical simulations. Simplified chemical kinetics was successfully implemented into a laminar fluid flow model applied to the complex burner geometry. Our methodical approach is based on the monitoring of flame emission, fast Fourier transformation and reproduction of measured spectral features by numerical simulations. Qualitative agreement between experimental and predicted oscillatory behaviour was obtained by employing a two-step methane oxidation scheme

Experimental investigations and numerical simulations of methane cup-burner flame

Pulsation frequency of the cup-burner flame was determined by means of experimental investigations and numerical simulations. Simplified chemical kinetics was successfully implemented into a laminar fluid flow model applied to the complex burner geometry. Our methodical approach is based on the monitoring of flame emission, fast Fourier transformation and reproduction of measured spectral features by numerical simulations. Qualitative agreement between experimental and predicted oscillatory behaviour was obtained by employing a two-step methane oxidation scheme

Erstellung einer Ozon-Kurzfristprognose fuer das Smogfruehwarnsystem. Verbesserung der Ozon-Kurzzeitprognose im Rahmen des Smogfruehwarnsystems Abschlussbericht

Das Ziel war die Entwicklung eines, gegenueber dem bis dahin verwendeten Verfahren verbesserten, routinemaessig einsetzbaren Modells zur bundesweiten Prognose des taeglichen Maximums der Ozonkonzentration. Es wurde ein Prognosesystem zur Vorhersage des bodennahen Ozons entwickelt. Folgende Verfahren wurden einbezogen: - ein statistisches Vorhersagemodul fuer die lokale Ozonvorhersage auf der Basis von ARMAX-Modellen; - das photochemische Ausbreitungsmodell REM3 zur flaechenhaften Vorhersage der grossraeumigen Ozonentwicklung; REM3-Ergebnisse werden als zusaetzliche Eingabeparameter fuer die auf statistischen bzw. Fuzzy-Modellen basierende lokale Ozonvorhersage verwendet. - Fuzzy- und Sugeno-Fuzzy-Systeme als Alternative zu dem klassischen statistischen Verfahren und zur Kombination aller Verfahren bei der Ozonprognose. - Entwicklung von Sugeno-Fuzzy-Systemen, die als Selbstlernsysteme eingerichtet werden koennen. Datenbasis fuer alle Verfahren sind die aktuellen meteorologischen lokalen und Feldprognosen des Deutschen Wetterdienstes, die aktuellen meteorologischen Beobachtungen und die Ozonmessungen des Umweltbundesamtes und der Laender. (orig.)The aim was the development of an ozone forecast system with an improved quality in relation to the old forecast tool at Federal Environmental Agency of Germany. A System has been developed to forecast ground level ozone over Germany: - a statistical module for local forecast on the basis of ARMAX-modeling - the photochemical transport model REM3 to forecast the Europeanwide formation of ozone. REM 3 forecast are used as additional parameter within statistical and Fuzzy modeling - Fuzzy and Sugeno-Fuzzy-models as an alternative to the classical statistical approach - development of a Neuro-Fuzzy system for automatic learning and adaptation of observation data. The data basis for all modules is given by meteorological realtime data and forecasts from the German Weather Service and ozone measurements of the Federal Environmental Agency and the German countries. (orig.)With CD-ROMAvailable from TIB Hannover: RN 8908(2000,175) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman