Subproject GV2: Shock-tube study of the chemical kinetics of incomplete oxidation reactions

The aim of this project is to investigate the kinetics of combustion reactions under conditions that are "unusual" for combustion research. This includes the investigation of the reaction of rich mixtures and interrupted reactions. The project will provide input and validation data for project GM1 (Maas) and well covers the range of high temperatures and short reaction times complementary to the conditions investigated in project MM1 (Maas/Schießl) in the Rapid Compression Machine. Of particular interest is the study of branching reactions, that on the one hand lead to the desired reaction products (e.g., unsaturated hydrocarbons), on the other hand also lead to unwanted polycyclic hydrocarbons (soot precursors). Moreover, the effect of additives (n-heptane, dimethyl ether, ethanol) on the reaction kinetics of methane / air mixtures will be investigated.

There experimental configurations will be used for the study of fast reactions at variable pressures and temperatures. (1) Behind the reflected shock waves intermediate and product concentrations will be investigated with high time resolution by high-repetition-rate time-of-flight mass spectrometry. (2) In a single-pulse shock tube, a gas mixture is heated to high temperatures for a short time and then cooled and examined the range of products by gas chromatography / mass spectrometry. (3) While the previous experiments are performed at around atmospheric pressure in dilute systems (reactant concentrations ~1% by volume), the transfer to undiluted systems and peak pressures up to some 100 bar is carried out in a high-pressure shock tube.