科研之友
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摘要
We report new results using laser-based imaging techniques (CH2O PLIF and Mie scattering) to understand the structure of turbulent dimethyl ether-based flames in comparison to well-studied methane-based flames. Specifically, the paper introduces a new set of potential target flames using DME fuel. The new DME-based flames are formulated with the specific intention of directly comparing non-intrusive laser-based measurements with the DLR A and B flames, which serve as target cases within the TNF workshop. The new DME-based flames are operated at equivalent Reynolds numbers and have an identical stoichiometric mixture fraction as the DLR flames, thus attempting to isolate kinetic effects and turbulence-chemistry interaction from flowfield and mixing effects. In this paper, we examine the CH2O field using planar laser-induced fluorescence (PLIF) and laser Mie scattering of fuel-seeded oil droplets which yield an approximate marker of the 700-800 K isotherms. Results from laminar flame calculations indicate that large amounts of CH2O are formed in DME-based flames as compared to CH4-based flames due to very rapid DME pyrolysis. Additionally, the calculations suggest significant differences in the topology of the CH2O distribution. Consistent with the laminar flame calculations, the measured CH2O PLIF signals from the turbulent DME-based flames are approximately two orders of magnitude higher than the DLR flames. Furthermore, instantaneous, average, and RMS images from the turbulent flames are used to highlight qualitative differences in the CH2O field for the DME-based flames in comparison with the methane-based DLR flames.
- 出版日期2013
