Investigation of fluid devices for mixing enhancemet for the shockless explosion combustion process

Abstract

Fuel-air mixing is a crucial process in low emission combustion systems. A higher mixing quality leads to lower emissions and higher combustion efficiencies. Especially for the innovative constant volume combustion processes ”Shockless Explosion Combustion” (SEC) the mixing of fuel and air is an important parameter, since the whole combustion process is triggered and controlled via the equivalence ratio. To enhance the passive scalar mixing, fluidic oscillators are investigated and compared to the standard jet in crossflow fuel injection configurations. The mixing quality of the different geometries is assessed in a water test-rig by making use of planar laser induced fluorescence. After a short introduction to the SEC-process, the test-rig and the different injection configurations are introduced. To verify whether the mixing quality is sufficient for the SEC-process, a numerical investigation using the experimentally determined unmixedness is conducted. It is not only shown that the fluidic oscillators are able to enhance the mixing quality and create an independence of the mixing quality from the jet in crossflow momentum, but it is also verified in a first numerical calculation that the achieved mixing quality might be good enough for the Shockless Explosion Combustion process.